Date   

Re: 7854 RAM card upgrade only - any interest?

 

On 10 Mar 2016 09:38:09 -0800, you wrote:

Some conclusions and a bit of speculation:

...

So now, how does the MPU decide which way to go at power
on time (to Self Test or to a simple startup using existing RAM contents)?

My speculation is that Self Test writes some marker bits in RAM that remain
there unless RAM power is lost. Self Test always runs at power on unless
backup power was supplied before the last power off and is not interrupted
until after the next power on. So I presume that at power on the MPU checks
the marker bits and runs Self Test if they are gone from RAM.
Tektronix recognized the problem you identify.

The added switch connects to the keyboard interface where the firmware
can read it to decide whether to initialize the battery backed up RAM
or maintain its contents. It is pretty clever; I remember studying
exactly how it worked a couple years ago.

The battery backed up RAM contents are always maintained by the
onboard lithium battery no matter how the switch is positioned. The
switch only alters the behavior of the firmware.

Now for the new Tek RAM/ROM card:
First, a speculation: the new low power RAM chips may hold their contents for a while after apparently losing power, making a marker bits test unreliable. Bypass caps on the backup power line would guarantee this for a considerable time. Certainly the new memory card does not use the BAT line according to the wiring diagram, nor does it ever remove power from the RAM chips. Does a newer MPU card look at the BAT line, unlike the older one? That would mean Tek made a firmware change to sense a new input from the rear panel switch. It is now unclear to me how we implement the switch, especially if we really don't want to modify the MPU card nor, ideally, the A32 card. I can imagine removing battery power and bleeding down the backup voltage as well with the switch, but this only works if the new firmware still does the marker bits test (which is far from certain).
The MPU card was unchanged so far as I know.

Just from inspection of the rear panel connector board schematic, it
looks like the new firmware will execute the self test on turn on
erasing the memory contents if the switch and logic circuit is not
installed.

Is there a full scan of the newest (B100000 version) 7854 manual available (or at least all of the wiring diagrams)? I would want to look at the motherboard, MPU card and A32 card wiring to try to shed more light on this.
I just finished updating my abbreviated schematics to show the B10000
version of the rear panel connector board schematic. There were also
some minor changes to the B110000 combined memory board but they are
not related to the firmware or battery backed up RAM behavior.

magnet:?xt=urn:btih:855FB846DE9BA7958AEEA6434B7BA2D9D754C1B6

I will also send a copy of the new torrent file to your email so you
can grab it if the magnet link does not work.

Cliff


Re: 7854 RAM card upgrade only - any interest?

 

8KBytes of RAM could be added where the unused patch ROM address space
is and this would be continuous with the existing 16KBytes of RAM for
a total of 24KBytes but it is not clear whether the existing firmware
would enumerate it.

On Thu, 10 Mar 2016 11:00:52 -0600, you wrote:

I am late reading this stream. Would it be possible to add more RAM to extend either the record length or, more likely, the number of traces and lines of program stored?

Charlie Conger


Re: 7854 RAM card upgrade only - any interest?

Cliff Carrie
 

Some conclusions and a bit of speculation:

First, the older (pre SN B100000) design:
The rear panel banana jacks go only to the rear panel connector board (A32). From there, the only output is the BAT line, which goes only to the motherboard MPU and RAM card sockets, pins 15 and R in both cases. On the RAM board, the only use is to supply the standby voltage to the RAM chips when the scope power is off. No signal leaves the RAM card to tell the MPU if standby power is on. Also, on the MPU card, pins 15 and R (the BAT line) ARE NOT CONNECTED TO ANYTHING. I verified this in the wiring diagram and on the actual card using a strong light from both sides and through the card (6 layers including 2 ground planes BTW). So now, how does the MPU decide which way to go at power on time (to Self Test or to a simple startup using existing RAM contents)? My speculation is that Self Test writes some marker bits in RAM that remain there unless RAM power is lost. Self Test always runs at power on unless backup power was supplied before the last power off and is not interrupted until after the next power on. So I presume that at power on the MPU checks the marker bits and runs Self Test if they are gone from RAM.


Now for the new Tek RAM/ROM card:
First, a speculation: the new low power RAM chips may hold their contents for a while after apparently losing power, making a marker bits test unreliable. Bypass caps on the backup power line would guarantee this for a considerable time. Certainly the new memory card does not use the BAT line according to the wiring diagram, nor does it ever remove power from the RAM chips. Does a newer MPU card look at the BAT line, unlike the older one? That would mean Tek made a firmware change to sense a new input from the rear panel switch. It is now unclear to me how we implement the switch, especially if we really don't want to modify the MPU card nor, ideally, the A32 card. I can imagine removing battery power and bleeding down the backup voltage as well with the switch, but this only works if the new firmware still does the marker bits test (which is far from certain).


Is there a full scan of the newest (B100000 version) 7854 manual available (or at least all of the wiring diagrams)? I would want to look at the motherboard, MPU card and A32 card wiring to try to shed more light on this.


Cliff


Re: 7854 RAM card upgrade only - any interest?

 

On 09 Mar 2016 22:12:13 -0800, you wrote:

The wiring diagram of the new Tek A28 board answers one mystery and raises another one. First, the vacant chip sites are for 2732 ROMs, not for added RAM.

With the other address map reserved areas you have identified and our lack of information about the firmware, I think this means we have no practical way to increase the RAM beyond the existing 8K words. Mystery solved, but no new goodies. We almost certainly do not need the vacant chip sites on our new card.
RAM could be placed into the ROM patch space from 8000 to 9FFF; it
would follow the pattern of adding RAM 2 pages at a time but in the
wrong place. Tektronix routed the ROM decode signal (-ROM) to the RAM
slot even though it was not needed; maybe the firmware enumerates RAM
in the patch ROM address space even though it was never needed.

I looked into what would be neccessary to modify my card to test this
but it would be too complicated to risk. The neccessary decode
circuit is already shown on the combined memory board; adjust the
pinout of the 2732 EPROMs to 6264 SRAMs (only half of the RAMs are
used) and route the existing write enable and PUP signals to them.

You mentioned that Tek somehow "sandwiched" the patch ROM content into the latest ROMs along with the existing coed. This is probably not quite true. The patch ROM and the FPLA chip act together to overlay bits of ROM code. On the new card, merging the patched code into the base ROMs probably requires no added space because the patches effectively replace bits of the earlier version code. The MPU gets either the original code or a replacement overlay depending on what the FPLA selects. The new ROMs roll the patches into the base code, eliminating the need for overlays.
The FPLA can only patch 48 areas and there are alignment restrictions.
The contents of the patch ROMs looks like they include the patch table
with overlay code which the FPLA uses and a separate block with 554
bytes of continuous code and data which is called by the patch
changes.

I never worked with TMS9900 assembly or machine code so I do not
recognize any opcodes.

Second, and a new mystery, the new Tek memory card has no connections for the Memory Backup / Self Test switch on the back panel of the scope. The switch may therefore be wired into some other card (MPU?). I will look into the old style MPU board tomorrow to see if the BAT line goes anywhere. It does go from the rear panel connector board to both the RAM and the MPU boards, but I don't see it in the MPU board diagram.

Cliff
Hmm, I saw the updates to schematic 36 somewhere which showed the
changes and where the new switch was attached but they are not in my
compiled documents.

I have updated my documents to include the updated combined memory
board used in serial number B11000 and greater and the changes to the
rear panel connector:

magnet:?xt=urn:btih:855FB846DE9BA7958AEEA6434B7BA2D9D754C1B6


Re: 7854 RAM card upgrade only - any interest?

 

I found two updated schematics including this one and started adding
them to my abbreviated PDF containing the 7854 schematics last night.
There were also some minor changes to the combined memory board for
serial number B110000 and above. My 7854 is slightly older than this
so my photos are of the older board.

On the rear panel connector board A32, U17 is a 74LS05 which is an
open collector hex inverter; three inverters are used and two 4.7k
pullup resistors. The 74LS05 can be replaced with a 74LS01 (Open
Collector Quad 2-input NAND Gate), a 74HCT05, a 74HCT01, or 3 NPN
transistors, 3 diodes, and 3 resistors.

The combined memory board has a delay of about 30 nanoseconds added to
the 74LS245 chip enable using two spare gates from U100 and a delay of
about 30 nanoseconds added to the 6264 RAM chip enable. Tektronix
also added additional decoupling capacitors to the SRAMs which operate
from the separate battery backed up Vcc supply.

Here are my updated 7854 files:

magnet:?xt=urn:btih:855FB846DE9BA7958AEEA6434B7BA2D9D754C1B6

On Thu, 10 Mar 2016 12:34:27 -0000, you wrote:

There's a new page <36> for a revised version of the A32 rear panel
schematic that shows the removal of the external power sockets and how that
switch is wired along with some inverters (U17 on A32) which were added.

I don't have the updated parts list for the IC type of the inverter but I'd
pretty much guess that 74ls04 or 74hc04 would do fine (though you might need
the HCT version).

If modifying an existing A32 you'd probably need to get inventive on
mounting and powering that IC.

Dave


Re: MAKING EXCELLENT PCBs using toner transfer

Malcolm Hunter
 

On 10 March 2016 at 16:52, Peter Hildebrandt petertech99h@...
[TekScopes] <TekScopes@...> wrote:

Jim Popwell & others interested – Plate thru holes The commercial
process: (short version) In fab shops I often visited for various new PCBs,
theprocess was like this:1- The 2 sided fully copper clad board
(includingmultiplayer boards) has tooling holes just outside the board
outline. 2 - The board is CNC drilled for all the holes. Usually thisis in
a stack of panels plus thin aluminum entry and exit panels to controldrill
wander and burrs.3- The boards are hung in a immersion copper plate
tank,copper lines the holes and also coats the foil.4 - The boards are
moved to an electro copper plate tank fora ‘plate up’ that also thickens
the coating in the holes. Holes are usuallydrilled .002” bigger so parts
still fit, critical if CNC thru hole partsinserter is used – back then.5 –
The boards are rinsed and dried then sensitized.6 – Boards are then aligned
with photomask of circuit tracesvia tooling holes and exposed.7 - Image is
thendeveloped and rinsed off. Negative image for next step. 8 - Since
solderplate is common, it goes to a plating tank. This plating becomes the
etching resist by covering the tracks. (For boards with a solder ink mask
thensolder plated pads a different process is used.)9 – With a plated
solder pattern, the original photoresistnegative image is stripped off. 10
– The board is now etched to remove unwanted copper onboth sides. –
Done! The at home process:The home process is a lot easier then you
think. If you want to do a lot of PCBs considerassembling a X Y CNC table
to guide a dremel over the board to make a lot ofboards, however there are
options: 1 - make a spare copy 1:1 scale for the circuit pattern youhave.2
- tape down the fully clad PCB to a flat wood base, tapeyour spare pattern
over it.3 - Use a dremel in a dremel drill press or free hand anddrill
straight holes thru your pattern and the PCB. (Dremel did have a mini 3jaw
chuck the can hold # 30 to # 60 drills, I’ve got one)4- source
some‘immersion copper plating solution’ (ask for an ‘engineering sample’ ie
1 litre/ quart or buy as needed) then soak the board and agitate to pass
solution thruthe holes for 20 minutes or so, experiment with different
times on dummy parts.5 – source some ‘electro copper plate solution’, and
somesmall copper bars, rods or wire. Get a car battery 6V/12V charger of at
least10 Amps. Set up a tank or tray. Controlthe current by switching 6V or
12V and spacing the copper rods further from thePCB and also the size of
the copper anodes actually in the solution. Plate for 30 minutes at 10A to
20A. Agitate the solution to keep fresh solutionnear the holes.6 – Dry the
board. Sensitize, image and develop your way.7 – At the point you start the
etching, plug each hole fromboth sides with masking compound, let dry, to
be sure the holes don’t getetched out, then etch.8 – As mentioned earlier,
Ferric chloride diluted with hot/warm water etched better then 100 % ferric
chloride. Go figure!8 – Dry the board and pick off the masking compound and
testyour plate thru holes for continuity! Done! 9 – (I also did selective
gold plating on PCBs at home,easier then it sounds, looks good too!!)

​Wow! Was that formatted correctly when you sent it?

Malcolm​


[Non-text portions of this message have been removed]


Re: 7854 RAM card upgrade only - any interest?

Nathan Johnson
 

It appears to be very unlikely without doing some really in-depth reverse
engineering of the firmware, quite beyond my ability.
Nathan KK4REY

Sent using CloudMagic Email
[https://cloudmagic.com/k/d/mailapp?ct=pi&cv=7.4.15&pv=9.1&source=email_footer_2]

On Thu, Mar 10, 2016 at 20:00, Charlie Conger ctconger@... [TekScopes]
<TekScopes@...> wrote:
I am late reading this stream. Would it be possible to add more RAM to extend
either the record length or, more likely, the number of traces and lines of
program stored?

Charlie Conger



[Non-text portions of this message have been removed]


Re: 7854 RAM card upgrade only - any interest?

Charlie Conger
 

I am late reading this stream. Would it be possible to add more RAM to extend either the record length or, more likely, the number of traces and lines of program stored?

Charlie Conger


Re: MAKING EXCELLENT PCBs using toner transfer

petertech99h
 

Jim Popwell & others interested – Plate thru holes The commercial process: (short version) In fab shops I often visited for various new PCBs, theprocess was like this:1- The 2 sided fully copper clad board (includingmultiplayer boards) has tooling holes just outside the board outline.  2 - The board is CNC drilled for all the holes. Usually thisis in a stack of panels plus thin aluminum entry and exit panels to controldrill wander and burrs.3- The boards are hung in a immersion copper plate tank,copper lines the holes and also coats the foil.4 - The boards are moved to an electro copper plate tank fora ‘plate up’ that also thickens the coating in the holes. Holes are usuallydrilled .002” bigger so parts still fit, critical if CNC thru hole partsinserter is used – back then.5 – The boards are rinsed and dried then sensitized.6 – Boards are then aligned with photomask of circuit tracesvia tooling holes and exposed.7 -  Image is thendeveloped and rinsed off. Negative image for next step.  8 -  Since solderplate is common, it goes to a plating tank. This plating becomes the etching resist by covering the tracks.  (For boards with a solder ink mask thensolder plated pads a different process is used.)9 – With a plated solder pattern, the original photoresistnegative image is stripped off.  10 – The board is now etched to remove unwanted copper onboth sides. – Done!  The at home process:The home process is a lot easier then you think.  If you want to do a lot of PCBs considerassembling a X Y CNC table to guide a dremel over the board to make a lot ofboards, however there are options: 1 - make a spare copy 1:1 scale for the circuit pattern youhave.2 - tape down the fully clad PCB to a flat wood base, tapeyour spare pattern over it.3 - Use a dremel in a dremel drill press or free hand anddrill straight holes thru your pattern and the PCB. (Dremel did have a mini 3jaw chuck the can hold # 30 to # 60 drills, I’ve got one)4- source  some‘immersion copper plating solution’ (ask for an ‘engineering sample’ ie 1 litre/ quart or buy as needed) then soak the board and agitate to pass solution thruthe holes for 20 minutes or so, experiment with different times on dummy parts.5 – source some ‘electro copper plate solution’, and somesmall copper bars, rods or wire. Get a car battery 6V/12V charger of at least10 Amps.  Set up a tank or tray. Controlthe current by switching 6V or 12V and spacing the copper rods further from thePCB and also the size of the copper anodes actually in the solution.  Plate for 30 minutes at 10A to 20A.  Agitate the solution to keep fresh solutionnear the holes.6 – Dry the board. Sensitize, image and develop your way.7 – At the point you start the etching, plug each hole fromboth sides with masking compound, let dry, to be sure the holes don’t getetched out, then etch.8 – As mentioned earlier, Ferric chloride diluted with hot/warm water etched better then 100 % ferric chloride. Go figure!8 – Dry the board and pick off the masking compound and testyour plate thru holes for continuity! Done! 9 – (I also did selective gold plating on PCBs at home,easier then it sounds, looks good too!!)

On Monday, March 7, 2016 8:13 PM, "gmt1@... [TekScopes]" <TekScopes@...> wrote:


  Hi Folks,
You can make PCB boards of the highest quality using the toner transfer method.
The secret is to use Pulsar’s Transfer Paper and Pulsar’s Green TRF Foil (both products made in the US) and
a modified laminator .Pulsar products are sold worldwide i gather.

Use Ferric chlorides etchant.
I have no connection with Pulsar (just a happy customer)

I struggled for years to make decent PCBs and this is by far the best DIY system avaliable.
You can produce boards that match Photographic methods and make very fine tracks.
All electronic enthusiast should be able to make there own PCBs and produce there own TEK

extender boards relatively cheaply.
Not a lot of info on Pulsar,on the net, for some reason but i found this excellent writeup
from a local mob here in Australia see......
http://ultrakeet.com.au/write-ups/makepcbs http://ultrakeet.com.au/write-ups/makepcbs
Regards
George










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[Non-text portions of this message have been removed]


Repair of Tek 465 coarse/fine x-position pot

Tom Gardner
 

I recently obtained a non-functional 465 that had probably
been dropped. After replacing the CRT and HV diodes it
works well except for the fine x-position pot. Looking at
the geometry and construction, that looks like it would
be a common failure point.

The coarse x-position pot worked well, but fine x-position pot
didn't work unless you pulled out on the knob while turning.
Removing the fine position pot revealed its spindle moved
freely in and out. When fully pulled out and turned, the pot wiper
turned normally, but even when slightly pushed in, the spindle
lost contact with the wiper. I suspect the scope had been rested
face-down with weight on the knob, and that had pushed
the spindle and detached it from the wiper. Irritating, irksome,
but the scope could be used without it.

Any attempt to slip the knob over the spindle failed because the
slightest friction moved the spindle in.

After a few abortive attempts, the solution is simple and
effective. Put the coarse knob on as normal, then slip a spring
over the fine-position spindle. Carefully putting the fine knob
on again still fails, but now the spring pushes the fine knob out
sufficiently that it re-engages with the wiper.

Success.


dm504a for sale

 

Hi,


I have a auto ranging DM504A multimeter that needs calibration. I reads a bit low on most ranges. I do not have calibration equipment good enough to do this calibration. The 200mv and 2000mv scales are recalibrated for dcv. Make offer to me off list at
@jmassen418


Jerry Massengale


Re: Tektronic 466 - Storage Modes inop

 

The 5111 and 577 D1 both use bistable storage only. I've found the operation of (older) bistable storage systems mostly marginal. It is quite sensitive to temperature and periods of non-use but it does recover (mostly) after several hours under power.
The 466 has a different construction; it can benefit from being revived under power but far less so.

I have bistable storage 'scopes and several of the other types. I have always found that the non-bistable systems need far less recovery, like the 464, 466, 7613. I've seen the same differentiated behaviour in 'scopes using both systems, like the 7623A, 7633, 7834.

Bistable-only systems generally are older than the other systems, so with those, age may play a role in itself.

My 577 D1 and 5113 (bistable only, basically identical systems) need at least half an hour after being switched on to provide good storage. Scopes like the 464, 466 and 7834 just need a few minutes.

I think your 466 has a problem. Could just be a matter of voltage adjustments in the storage system.

Raymond


Re: 7854 RAM card upgrade only - any interest?

 

There's a new page <36> for a revised version of the A32 rear panel
schematic that shows the removal of the external power sockets and how that
switch is wired along with some inverters (U17 on A32) which were added.

I don't have the updated parts list for the IC type of the inverter but I'd
pretty much guess that 74ls04 or 74hc04 would do fine (though you might need
the HCT version).

If modifying an existing A32 you'd probably need to get inventive on
mounting and powering that IC.

Dave

-----Original Message-----
From: TekScopes@... [mailto:TekScopes@...]
Sent: 10 March 2016 06:12
To: TekScopes@...
Subject: Re: [TekScopes] 7854 RAM card upgrade only - any interest?

The wiring diagram of the new Tek A28 board answers one mystery and raises
another one. First, the vacant chip sites are for 2732 ROMs, not for added
RAM.

With the other address map reserved areas you have identified and our lack
of information about the firmware, I think this means we have no practical
way to increase the RAM beyond the existing 8K words. Mystery solved, but no
new goodies. We almost certainly do not need the vacant chip sites on our
new card.


You mentioned that Tek somehow "sandwiched" the patch ROM content into the
latest ROMs along with the existing coed. This is probably not quite true.
The patch ROM and the FPLA chip act together to overlay bits of ROM code. On
the new card, merging the patched code into the base ROMs probably requires
no added space because the patches effectively replace bits of the earlier
version code. The MPU gets either the original code or a replacement overlay
depending on what the FPLA selects. The new ROMs roll the patches into the
base code, eliminating the need for overlays.


Second, and a new mystery, the new Tek memory card has no connections for
the Memory Backup / Self Test switch on the back panel of the scope. The
switch may therefore be wired into some other card (MPU?). I will look into
the old style MPU board tomorrow to see if the BAT line goes anywhere. It
does go from the rear panel connector board to both the RAM and the MPU
boards, but I don't see it in the MPU board diagram.


Cliff






------------------------------------
Posted by: test2cal@...
------------------------------------


------------------------------------

Yahoo Groups Links


Looking for 067-1331-00 Sampling Head Simulator. WTB.

Egge Siert
 

Hi to All,


Looking for this Service Fixture. Some years ago USA Only Seller CHIPXS sold tenths of them for little money. But that was before I got addicted to the 11K Series. Anybody who wants to seperate from such a device?


Greetings,


Egge Siert


Re: Tektronic 466 - Storage Modes inop

Tim Phillips <tim@...>
 

from Tim P (UK)
Aha !! The manual for the 5111 storage 'scope specifies a turn-on procedure for an instrument that has not been used for a while (2 wks) or from new.
With power OFF, Upper and lower store ON, brightness MAX, power up. This "reduces the ion content in the CRT" (from the manual), wait for the screen to flood. After 5 minutes ,do a couple of Erases, then U/L Store OFF. The full story is on pp1-4 of the 5111 manual, but, of course, I don't know whether this procedure is specific to the 5000 storage scopes or even that CRT.
Tim

----- Original Message -----
From: "edbreya@... [TekScopes]" <TekScopes@...>
To: <TekScopes@...>
Sent: Thursday, March 10, 2016 3:54 AM
Subject: [TekScopes] Re: Tektronic 466 - Storage Modes inop


I don't know if this will help, but it may be a good idea to let it cook for a few hours, especially if it hasn't been run in a few years. I have a 577 D1 storage type on which the display looks awful when first turned on, in storage mode, with a big pincushion green background that can't be turned off. After running for about twenty minutes, and a few erase cycles, it blanks out nicely.

If it doesn't settle down, you may want to check and tweak the flood gun circuits. Once the basic operation is confirmed, you can check the screen and storage mesh by filling the display - just set up for a free-running sweep, and work the vertical position up and down until the whole thing is written. Ideally, it should present a uniform filled green screen. You'll see any bad spots or after-images.

Ed



Re: 7854 RAM card upgrade only - any interest?

Cliff Carrie
 

The wiring diagram of the new Tek A28 board answers one mystery and raises another one. First, the vacant chip sites are for 2732 ROMs, not for added RAM.

With the other address map reserved areas you have identified and our lack of information about the firmware, I think this means we have no practical way to increase the RAM beyond the existing 8K words. Mystery solved, but no new goodies. We almost certainly do not need the vacant chip sites on our new card.


You mentioned that Tek somehow "sandwiched" the patch ROM content into the latest ROMs along with the existing coed. This is probably not quite true. The patch ROM and the FPLA chip act together to overlay bits of ROM code. On the new card, merging the patched code into the base ROMs probably requires no added space because the patches effectively replace bits of the earlier version code. The MPU gets either the original code or a replacement overlay depending on what the FPLA selects. The new ROMs roll the patches into the base code, eliminating the need for overlays.


Second, and a new mystery, the new Tek memory card has no connections for the Memory Backup / Self Test switch on the back panel of the scope. The switch may therefore be wired into some other card (MPU?). I will look into the old style MPU board tomorrow to see if the BAT line goes anywhere. It does go from the rear panel connector board to both the RAM and the MPU boards, but I don't see it in the MPU board diagram.


Cliff


Re: MAKING EXCELLENT PCBs using toner transfer

Ed Breya
 

Haha. That reminds me of how I etched boards when I was a kid - with ferric chloride solution in a Pyrex cake pan on the electric range in the kitchen. My mother didn't appreciate it, and threatened numerous times to kill me if I ever stained her white Formica counter tops. I never did, although there was a close call once with some potassium permanganate from an experiment - if you clean up quickly, Formica is amazing stuff.

Ed


Re: MAKING EXCELLENT PCBs using toner transfer

petertech99h
 

Hi all, In the days 'BC' (before CAD) I used Red and Blue mylarlayout tapes and black adhesive IC pad shapes scaled 2X to do double sidedPCBs.  The artwork got sent out and photographed with filters to produce 2production films, 1 top, 1 bottom, black pads showed up on both films,overlapping red and blue produced black traces on both sides. In high school I did a double-sided PCB making 2 artworksover a drafted layout with layout targets just outside the board outline thenimage the board one side at a time with 2 plates of glass and the board andartworks sandwiched inside. The secret to good etching at home with ferric chloride, isto dilute it 50% with hot water and keep a small heat lamp on the tank. I putrubber grommets on the corners of the PCB to space it up high enough to etchunderneath. Place in a flat glass cassarole dish fill with just enough etchantto cover the top of the PCB, then rock the dish at the right speed to get theetchant to sweep across the length of the board!  Results where great, no pitting, uneven edges and a 5-6 minuteetch!!, rather fast! Basically you could etch a board with 1 cup of 50/50solution and it would turn green by the time you where done, very little waste. I learned this technique from a techwho in the early days made the proto boards in house. He also made a jig with aslow stepper motor and an off-center roller to lift the edge of the dish to gentlyslosh the etchant on the boards, he made it big enough to do 4 different PCBs in4 different trays at the same time!

Is anyone interested how plate-thru holes are made? or iseveryone up to speed on that?  It’s possible to do that at home too!

Lots of fun, still have my first ever double sided boardsplus a spare!

Pete

On Monday, March 7, 2016 8:13 PM, "gmt1@... [TekScopes]" <TekScopes@...> wrote:


  Hi Folks,
You can make PCB boards of the highest quality using the toner transfer method.
The secret is to use Pulsar’s Transfer Paper and Pulsar’s Green TRF Foil (both products made in the US) and
a modified laminator .Pulsar products are sold worldwide i gather.

Use Ferric chlorides etchant.
I have no connection with Pulsar (just a happy customer)

I struggled for years to make decent PCBs and this is by far the best DIY system avaliable.
You can produce boards that match Photographic methods and make very fine tracks.
All electronic enthusiast should be able to make there own PCBs and produce there own TEK

extender boards relatively cheaply.
Not a lot of info on Pulsar,on the net, for some reason but i found this excellent writeup
from a local mob here in Australia see......
http://ultrakeet.com.au/write-ups/makepcbs http://ultrakeet.com.au/write-ups/makepcbs
Regards
George








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Re: MAKING EXCELLENT PCBs using toner transfer

Jim Popwell <jpopwell@...>
 

Hi Pete,
i’d like any pointers on plated thru hole at home….
if you can point me to any sites, thanks…
jim

On Mar 9, 2016, at 7:45 PM, Peter Hildebrandt petertech99h@... [TekScopes] <TekScopes@...> wrote:

Hi all,
In the days 'BC' (before CAD) I used Red and Blue mylar layout tapes and black adhesive IC pad shapes scaled 2X to do double sided PCBs. The artwork got sent out and photographed with filters to produce 2 production films, 1 top, 1 bottom, black pads showed up on both films, overlapping red and blue produced black traces on both sides.
In high school I did a double-sided PCB making 2 artworks over a drafted layout with layout targets just outside the board outline then image the board one side at a time with 2 plates of glass and the board and artworks sandwiched inside.
Is anyone interested how plate-thru holes are made? or is everyone up to speed on that? It may be possible to do that at home too!

Lots of fun, still have the boards plus a spare!
Pete

On Tuesday, March 8, 2016 12:59 AM, "'Dennis Tillman' @Dennis_Tillman_W7pF <mailto:@Dennis_Tillman_W7pF> [TekScopes]" <TekScopes@... <mailto:TekScopes@...>> wrote:


Hi Dave,
Me too. Plus OSHPark boards are gold coated which is very unusual and very prettyl!!!.
Dennis Tillman W7PF

-----Original Message-----
From: TekScopes@... <mailto:TekScopes@...> [mailto:TekScopes@... <mailto:TekScopes@...>]
Sent: Monday, March 07, 2016 9:31 PM
To: TekScopes@... <mailto:TekScopes@...>
Subject: Re: [TekScopes] MAKING EXCELLENT PCBs using toner transfer

I have been very happy getting boards made by OSHpark.com <http://oshpark.com/>, who offer both two and four layer small quantity fabrication at a reasonable price.

I did buy the Pulsar kit, but only with the intention of using it for certain projects where I felt it would be more cost effective than using a fab (such as a large area board of which I only plan to make one copy).

Dave Casey

On 3/7/2016 10:34 PM, 'Dennis Tillman' @Dennis_Tillman_W7pF <mailto:@Dennis_Tillman_W7pF> [TekScopes]
wrote:

Hi George, Dave, et al,
I made my own PC Boards back in the 1960s using a variety of methods
including photolithography, toner transfer, PC layout tape, and
special ink pens. The problem with all of these methods is you can
realistically only do single sided boards.

I worked out a way to do double sided boards but I first had to design
and build a very accurate jig to hold the boards and the photomasks in
perfect alignment under hot lights for several minutes. Even with all
that, there was still no way to do plated through holes. In most cases
I was clever enough to make the connections from one side of the board
to the other by carefully choosing where the via was located so it
corresponded to where a part would be placed. Then the lead from the
part or IC did double duty by acting as a via.

If you want to do a PC Board today it seems to me that a better use of
your time would be ExpressPCB which has free software. It is a
do-it-yourself solution to PCB layout but they can handle up to 4
layer boards with vias, and they do silk screen layers on the top, and
(I think) the bottom as well. A big plus is you can learn it quickly
but it doesn't do much more than board layout. The biggest drawback is
you have to buy your boards from them and you have to buy 4 boards at
a time. Prices are reasonable. (I have no financial connection with them).

Dennis Tillman W7PF

-----Original Message-----
Sent: Monday, March 07, 2016 5:52 PM
Subject: Re: [TekScopes] MAKING EXCELLENT PCBs using toner transfer

Their website is http://www.pulsarprofx.com <http://www.pulsarprofx.com/>

Regards,

Dave Casey

On 3/7/2016 7:13 PM, gmt1@... <mailto:gmt1@...> [TekScopes] wrote:

Hi Folks,
You can make PCB boards of the highest quality using the toner
transfer method.
The secret is to use Pulsar’s Transfer Paper and Pulsar’s Green TRF
Foil (both products made in the US) and a modified laminator .Pulsar
products are sold worldwide i gather.

Use Ferric chlorides etchant.
I have no connection with Pulsar (just a happy customer)

I struggled for years to make decent PCBs and this is by far the
best DIY system avaliable.
You can produce boards that match Photographic methods and make very
fine tracks.
All electronic enthusiast should be able to make there own PCBs and
produce there own TEK

extender boards relatively cheaply.
Not a lot of info on Pulsar,on the net, for some reason but i found
this excellent writeup from a local mob here in Australia see......
http://ultrakeet.com.au/write-ups/makepcbs <http://ultrakeet.com.au/write-ups/makepcbs>
http://ultrakeet.com.au/write-ups/makepcbs <http://ultrakeet.com.au/write-ups/makepcbs>
Regards
George








[Non-text portions of this message have been removed]

[Non-text portions of this message have been removed]

------------------------------------
Posted by: Dave Casey <dcasey@... <mailto:dcasey@...>>
------------------------------------

------------------------------------

Yahoo Groups Links

[Non-text portions of this message have been removed]

------------------------------------
Posted by: Dave Casey <dcasey@... <mailto:dcasey@...>>
------------------------------------

------------------------------------

Yahoo Groups Links

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453 SN: 043226 Anode Now Solid State

Joseph Rooney
 

Chasing down a gain change warmup problem, I decided to replace the 5642's in the anode with replacements I found on line. Pictures here: https://flic.kr/p/EV6GoL https://flic.kr/p/EV6GoL https://flic.kr/p/EV6GQ7 https://flic.kr/p/EV6GQ7 after replacement of 5642's with two ESJA52-10 from HVStuff.com . Didn't fix the problem, I had to order them from China, took less than a week. Found 5kv rectifiers at Halted that were just too big to be in series. https://flic.kr/p/F6Ajfn https://flic.kr/p/F6Ajfn


These are far smaller than the 152-0408-00 we routinely used at Tektronix to replace 5642's and I'm quite sure they will work in your 5642 replacement scheme.


Joe