Date   

Re: 11801 questions - funny fan noise and light

Ragnar S
 

Thank you gentlemen for your replies!

So it is unclear if it is supposed to do this, but it is at least not
unheard of.

I checked the voltages on the feed wires to the fan relative chassis ground.
From start, the positive wire has about +6.3 V and the negative about +0.7 V.
When the fan revving occurs, the negative wire goes to about -6 V for about
35 ms, making a total voltage over the fan of about 12 V. For some reason
the pulses come irregularly, around 1 or a few times per second.

My current hypotheses is that the intention is to regulate the speed of
the fan, but I would be surprised if this actually is how it was designed
to work. It is somewhat annoying. :-)

Are there any schematics on these boxes to be found?


Also - the neon (?) light in the power supply, right behind the fan, that
starts to flicker as soon as it has power (also in standby mode) - do you
guys have that too?


Thanks for you help and best regards,

Ragnar

On 25 Jan 2020, at 16:01, Chuck Harris <cfharris@...> wrote:

Mine is normal until after the scope has been turned on for
about 30 minutes, and then it starts going "Brummm..... Brummm..."

I suspect a capacitor failure, as it is annoying, and would have
caused notice if it were a "normal" condition.

Annoying, though it may be, I can't see how it would cause any
harm... unless it presages a total failure.

What it isn't is a bearing failure, or lack of lubrication. My
fan spins for what seems like half a minute after power is turned
off.

-Chuck Harris

Reginald Beardsley via Groups.Io wrote:
I don't recall mine ever doing that. I'm very sensitive to noise as I investigate anything I can't identify, so I think I would have noticed it.

A fan on one of my HP Z400 workstations was doing that. I shut it down to reduce the heat in the room and when I tried to boot it the fan was dead. I've not had time to correct it yet.

Good luck,
Reg




Re: P6201 probe Q100 FET replacement

Nenad Filipovic
 

Thanks for your inputs, the probe is working, I decided to go with the
datasheet and mounted the FET upside down. R150 had to be decreased from
2kOhm to about 1.45kOhm for proper biasing. It needs calibration though,
but for that I'd need to assemble a proper rig.

Best Regards,
Nenad


Re: 2400 series Test 4 Fail 3,13, 1

Chuck Harris
 

Details matter.

The NEC uPD4364-20L draws 100ua max standby current.
The NEC uPD4364-20LL draws 50ua max standby current.

The maximums are at maximum temperature, which in
this case is 70C. At room temperature, the current
will generally be much lower, but is not guaranteed
to be so.

Why did you replace the original RAM chip?

-Chuck Harris

Craig Cramb wrote:

Dealing with 3 scopes all having the Test4 Failures
2465A S/N B011512 Test4 Fail 3 (Fixed)
2465B S/N B010817 Test4 Fail 13 ( This Post)
2465A DM S/N B010824 Test 4 Fail 2 (Haven’t started)

Thank to all for the info in this post. This has been long journey but glad to see an underlying condition could be existing.
I’m looking at completing the repair of the 2465B instrument pre 50,000 S/N. Got started on it about 6 months ago troubleshooting with help from members. Did the repair by replacing the U2460 (original part # NEC D4364C-15LL, replaced with part # NEC D4364C-20L) and replaced the Dallas Keeper battery purchased from Mouser.
That was June 2019. Other things took my interest so just now getting back to calibration. After doing the required calibration I kept getting diagnostic
of test 04 fail 13, Test 04 fail 11, Test 06 fail 01, then back to test 04 fail 01. Couldn’t seem to get ahead of it. So did what I should have done before attempting the calibration and checked the battery voltage. Yea I found it at .6VDC. No wonder I’m dealing with these faults.
So now onto why would the battery be drained in 6 months. The old battery I removed that was from the 1988 vintage was in the same condition so I just thought changing it 6 months ago would allow for another 10 yrs. But that wasn’t the case. So tracing thru the circuit there isn’t anything that I see that would allow for a quick drain of this battery. Feeding two IC, an amplifier, and two caps. Not sure how long it took to drain the battery.

Craig




Re: 2465B - Weak Readout Intensity

tekscopegroup@...
 

On Sat, Jan 25, 2020 at 09:50 AM, <flanneltuba@...> wrote:

Also let me add my "+" to the massively informative, if not exasperatingly
long and multilayered EEVBlog "2465B Teardown" thread. I spent hours pouring
over that thread—hours well spent for anyone diving into a 2565B
restoration. It was that thread that essentially illustrated the finer points
of repairing the later model A5 board with its notorious leaky 'lytics.

- Scott
Only hours? I spent several days sequentially reading all the posts, then again I went from page 1 and on (didn't want to miss anything crucial) and taking notes along the way. Glad you found it was helpful information. If you got the time I would even suggest that you might send in your own adventure with your scope so it will be added to the thread for future reference. I don't recall anybody over there ever reporting anything similar to your case.


Re: Your generosity is STUNNING!

Lawrance A. Schneider
 

Mr. Pope wrote: And to think that I felt guilty about only being able to give $5.00.
I could not get anything to work; I made no contribution. Something about hidden email address; whatever!!!
++++++++++++
However!! Keep whatever (except for those wanting it back) and put in an account for future needs. This has become a huge amount of work for Mr. Tillman. SAVE YOUR EFFORTS for something more meaningful. We all love the group. Having money put away for the future saves work by not needing to do this again for a long time.

larry


Re: TDS3012B to TDS3052B upgrade

 

On Sun, Jan 26, 2020 at 04:55 AM, Tom B wrote:


I have seen a lot of postings from people who have upgraded the bandwidth of
their TDS3000 scopes with firmware.   I have a TDS3012B that I was thinking
about doing that with but it seems strange that you could go from 100MHz to
500MHz without any hardware changes.  What I want to know is; how well does
this work?  Are there any issues to watch out for?
I have done that upgrade on several TDS3000 scopes including my own TDS3014B. It works fine
and it does not need an adjustment after the change. It's done with GPIB. It can also be done on
TDS200 and TDS1000/2000 but they need a full adjustments sequence to be done.

I have written several softwares to do a Performance Check on most of the older TDS's and for
the TDS's mentioned above I included a procedure to change the type. Initially I had an idea to
charge a small fee for that specific function. I have later abandoned this idea but until the software
has been changed you will need to get a key from me.

Find it here: http://www.hakanh.com/dl/TDS_pv.htm

/Håkan


Re: Your generosity is STUNNING!

 

Jay: you don't get a 'show quoted text' button w/Dennis' mesg?
No, but I get the digest so perhaps that's why?


Re: FW: CRT database and Stan's Reprise database of 151 part numbers

tek_547
 

Very usefull piece of information, thanx!!
René


Re: Your generosity is STUNNING!

 

Hi Jay,
That's strange. I did include the context. Here is my complete reply (between the long dashed lines).
For some reason you didn't everything in my reply. I don't know why.
Could this be why we don’t get context when other people DO include it in their replies?

Dennis Tillman W7PF
--------------------------------------------------------------------------------

-----Original Message-----
From: Dennis Tillman W7PF [mailto:@Dennis_Tillman_W7pF]
Sent: Friday, January 24, 2020 10:40 PM
To: 'TekScopes@groups.io' <TekScopes@groups.io>
Subject: RE: [TekScopes] Your generosity is STUNNING!

Hi Dave,
Fortunately that day is very far off.
Dennis Tillman W7PF

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of DaveH52
Sent: Sunday, January 19, 2020 12:33 PM
To: TekScopes@groups.io
Subject: Re: [TekScopes] Your generosity is STUNNING!

Maybe ask for just one dollar next time.
Enjoy your new DMM!
--------------------------------------------------------------------------------

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Jay Walling via Groups.Io
Sent: Saturday, January 25, 2020 6:18 AM
To: TekScopes@groups.io
Subject: Re: [TekScopes] Your generosity is STUNNING!

Hi Dave,
Fortunately that day is very far off.
Dennis Tillman W7PF
Say, didn't you just post about putting context in replies? ;^)

Jay





--
Dennis Tillman W7PF
TekScopes Moderator


Re: Your generosity is STUNNING!

 

Hi Larry,
Yes, I had no idea PayPal gave me a different transaction number that it gave you. This is why you could not find your transaction number in my list.
This is the information I have on your contribution (which I did receive):

### DENNIS' LOCAL TIME $$$ STATUS CONTRIBUTOR PAYPAL TRANSACTION
12 Tue 12/31/2019 12:32 AM $5.00 ACCEPT DONATION Larry McDavid 5L6310441C770780F

Thank you for your contribution,
Dennis

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Larry McDavid
Sent: Monday, January 20, 2020 11:43 AM
To: TekScopes@groups.io
Subject: Re: [TekScopes] Your generosity is STUNNING!

I don't want to beat this issue to death, but the comment below is very interesting. I could not find my PayPal transaction number in the list either and I wrote Dennis privately to explain that. But, mine was *not* an international transaction; I live in California. My donated amount is a common amount so I could not identify it by the amount.

So, I wonder if PayPal changes *all* the transaction numbers. Did anyone actually find his transaction number in the list Dennis published?

It is gratifying that so many did donate and I fully support the reimbursement; it is money well deserved.

Larry W6FUB

On 1/20/2020 9:45 AM, Raymond Domp Frank wrote:
Dennis,
My transaction could well be
9SK43*******0851N $22.57 TO BE REFUNDED
That's the only transaction in your list for the amount that I transferred.
Siggi may be right in assuming that Paypal references change between sender and receiver (nice!) for international transactions....
--
Best wishes,

Larry McDavid W6FUB
Anaheim, California (SE of Los Angeles, near Disneyland)


Re: Your generosity is STUNNING!

 

Hi Raymond,

You are one of the few people who did correctly identify your contribution in my list.
This is the information I have on your contribution:
### DENNIS' LOCAL TIME $$$ STATUS CONTRIBUTOR PAYPAL TRANSACTION
128 Wed 1/1/2020 2:50 PM $22.57 TO BE RETURNED Raymond Domp Frank 9SK435895B100851N

Yes, Siggi is correct PayPal did this for everyone. They also obscure the time you made your contribution because they strip out your UTC offset (time zone) so I can’t tell the hour of the day you sent it. The minutes are close however.

Thank you for your contribution. We received too much money to keep it all so we will be refunding anything above $10.00 as soon as I have had a chance to contact everyone who asked for confirmation that I received their contribution.

Dennis

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Raymond Domp Frank
Sent: Monday, January 20, 2020 9:45 AM
To: TekScopes@groups.io
Subject: Re: [TekScopes] Your generosity is STUNNING!

Dennis,
My transaction could well be
9SK43*******0851N $22.57 TO BE REFUNDED
That's the only transaction in your list for the amount that I transferred.
Siggi may be right in assuming that Paypal references change between sender and receiver (nice!) for international transactions.

Raymond


FW: CRT database and Stan's Reprise database of 151 part numbers

 

This is the reply from Dave Brown at the vintageTEK Museum regarding the CRT
catalog the museum was working on. It is available at
https://vintagetek.org/crt-database/

Dave said he does not remember Stan's Reprise data base of 151 part numbers.
Dave also said the reprise database is gone forever.

I (Dennis) only remember Stan and Bill's CRT database.
Dennis Tillman W7PF

-----Original Message-----
From: Dave Brown [mailto:davebr@...]
Sent: Saturday, January 25, 2020 10:25 AM
To: @Dennis_Tillman_W7pF
Subject: RE: CRT database

The CRT database https://vintagetek.org/crt-database/ has all the
information. It is just not in the form of a database so the user has to
spend maybe 5 minutes to find the data. The reprise database is gone
forever.

I don't remember the 151- database but it is also gone forever. However, all
that information is in the common parts catalogs which we got a release for
and are on Tekwiki. Again, someone has to find the 151- to manufacturer
pages in the transistor/diode book on Tekwiki and look it up. I assume that
is where the database actually came from. Attached but here is the link to
the document.

http://w140.com/tek_common_design_parts_catalog_transistors_diodes_and_misc_
may_1988.pdf



Dave

-----Original Message-----
From: Dennis Tillman W7PF [mailto:@Dennis_Tillman_W7pF]
Sent: Friday, January 24, 2020 9:18 AM
To: 'Dave Brown'
Subject: CRT database

Hi Dave,
Did you ever finish compiling all the CRT part numbers from the fiche?
I seem to recall you were also trying to get the CRT data that used to
be on Stan Griffiths and Bill's DenBeste's (not sure of the spelling) web
site.
Also, are you familiar with Stan's Reprise database of 151 part numbers?
That came up in a post to TekScopes. I'm not familiar with it but
apparently
it is no longer available.
Dennis


--
Dennis Tillman W7PF
TekScopes Moderator


Re: TDS3012B to TDS3052B upgrade

Dave Casey
 

It works because the hardware was designed for the 500MHz bandwidth from
the beginning. The firmware limits the bandwidth based on model number.
That said, there is some debate as to whether there was any "binning" of
hardware based on performance (such that scopes which didn't meet spec at
500MHz but did at 300MHz became TDS3032s and 3034s instead of 3052s and
3054s). This doesn't mean that such a scope wouldn't be usable at higher
frequencies if the bandwidth limitation were removed, just that it might
not meet Tek's advertised specs. There's another camp that says they're all
good to the full bandwidth, carte blanche. Either way, your 3012 was
probably not calibrated above 100MHz, so if you do the upgrade you may not
realize the full benefit without a calibration.

Dave Casey

On Sat, Jan 25, 2020 at 9:55 PM Tom B <tbryan@...> wrote:

Hello All,

I have seen a lot of postings from people who have upgraded the
bandwidth of their TDS3000 scopes with firmware. I have a TDS3012B
that I was thinking about doing that with but it seems strange that you
could go from 100MHz to 500MHz without any hardware changes. What I
want to know is; how well does this work? Are there any issues to watch
out for?

Tom Bryan
N3AJA






TDS3012B to TDS3052B upgrade

Tom B
 

Hello All,

I have seen a lot of postings from people who have upgraded the bandwidth of their TDS3000 scopes with firmware.   I have a TDS3012B that I was thinking about doing that with but it seems strange that you could go from 100MHz to 500MHz without any hardware changes.  What I want to know is; how well does this work?  Are there any issues to watch out for?

Tom Bryan
N3AJA


Re: Your generosity is STUNNING!

p mc
 

Jay: you don't get a 'show quoted text' button w/Dennis' mesg?

On Sat, Jan 25, 2020 at 06:18 AM, Jay Walling wrote:


Hi Dave,
Fortunately that day is very far off.
Dennis Tillman W7PF
Say, didn't you just post about putting context in replies? ;^)

Jay


Re: 2465B - Weak Readout Intensity

flanneltuba@...
 

On Fri, Jan 24, 2020 at 01:12 AM, satbeginner wrote:

The 2465x uses what I call a "fly by wire" control system.
...
The sample and hold circuits are build using a simple opamp circuit.
The output of the analog switch charges a capacitor, and the high input
impedance of the opamp keeps it at the presented level.
The opamp shifts the level depending on what the functionality needs.

I have seen these sample capacitors go bad as well as the opamps. (TLO72???)
Thank you for pointing this out! This illuminates an entire section of the DAC "fly by wire" circuit that I have heretofore overlooked.
Certainly before I go to the monumental effort of performing a CRT swap, I will sniff my way carefully thought this MUX'd sample-and-hold circuitry.

I have ordered a CRT, which hopefully will be of the 2465A/B flavor, but I'd be nothing but glad to just put it up on a shelf or resell it instead of having to install it!

Also let me add my "+" to the massively informative, if not exasperatingly long and multilayered EEVBlog "2465B Teardown" thread. I spent hours pouring over that thread—hours well spent for anyone diving into a 2565B restoration. It was that thread that essentially illustrated the finer points of repairing the later model A5 board with its notorious leaky 'lytics.

- Scott


Re: P6201 probe Q100 FET replacement

Gary Appel
 

I think that years ago I got some replacement FETs from Dean Kidd, and they had to be mounted upside down because the lead configuration was reversed.

Gary Appel

On 1/25/2020 12:59 AM, Nenad Filipovic wrote:
Dear Group,

I got a dead P6201 off eBay, and everything points to a defective input FET
(probe serial B065531). So I obtained a handful of MMBF4416 (code
151-5025-00 in the service manual, factory default for later serial
numbers). Tek also released a product modification document under
050-1413-01 code:

http://bee.mif.pg.gda.pl/ciasteczkowypotwor/Tek/050-1413-01.pdf
same document:
http://hakanh.com/dl/docs/kitinstructions/050-1413-01.pdf

outlining this replacement. The problem I have now is that drain and source
of the 151-5025-00 FET in the above document are reversed compared to
MMBF4416. None of the datasheets for MMBF4416 say it's symmetrical, and I
somehow doubt an RF JFET would be without optimizations on the drain side.
This comment however states it is symmetrical:

https://groups.io/g/TekScopes/message/131217

but I see no facts this claim is based on. Does anyone have direct
experience with this particular replacement and D-S polarity? Disassembling
the probe head is a pain, I'd like to get this right on the first go.

Best Regards,
Nenad


Re: 2400 series Test 4 Fail 3,13, 1

GerryR <totalautomation1@...>
 

Craig,
My guess would be that you got an old battery from Mouser. I purchased mine from Mouser a few months back, and it came with no date code stamped on it, so who knows how long its been on the shelf. Mine is still working, however, and the one that I took out with a date code of 07-87 still has its full voltage on it. If my new battery fails anytime soon, Mouser is going to hear about it! The calibration process, as you know is quite a tedious process.
Regards,
GerryR
KK4GER

----- Original Message -----
From: "Craig Cramb" <@Manfromtrane>
To: <TekScopes@groups.io>
Sent: Saturday, January 25, 2020 12:02 PM
Subject: Re: [TekScopes] 2400 series Test 4 Fail 3,13, 1


Dealing with 3 scopes all having the Test4 Failures
2465A S/N B011512 Test4 Fail 3 (Fixed)
2465B S/N B010817 Test4 Fail 13 ( This Post)
2465A DM S/N B010824 Test 4 Fail 2 (Haven’t started)

Thank to all for the info in this post. This has been long journey but glad to see an underlying condition could be existing.
I’m looking at completing the repair of the 2465B instrument pre 50,000 S/N. Got started on it about 6 months ago troubleshooting with help from members. Did the repair by replacing the U2460 (original part # NEC D4364C-15LL, replaced with part # NEC D4364C-20L) and replaced the Dallas Keeper battery purchased from Mouser.
That was June 2019. Other things took my interest so just now getting back to calibration. After doing the required calibration I kept getting diagnostic
of test 04 fail 13, Test 04 fail 11, Test 06 fail 01, then back to test 04 fail 01. Couldn’t seem to get ahead of it. So did what I should have done before attempting the calibration and checked the battery voltage. Yea I found it at .6VDC. No wonder I’m dealing with these faults.
So now onto why would the battery be drained in 6 months. The old battery I removed that was from the 1988 vintage was in the same condition so I just thought changing it 6 months ago would allow for another 10 yrs. But that wasn’t the case. So tracing thru the circuit there isn’t anything that I see that would allow for a quick drain of this battery. Feeding two IC, an amplifier, and two caps. Not sure how long it took to drain the battery.

Craig


Re: 2400 series Test 4 Fail 3,13, 1

Craig Cramb
 

Dealing with 3 scopes all having the Test4 Failures
2465A S/N B011512 Test4 Fail 3 (Fixed)
2465B S/N B010817 Test4 Fail 13 ( This Post)
2465A DM S/N B010824 Test 4 Fail 2 (Haven’t started)

Thank to all for the info in this post. This has been long journey but glad to see an underlying condition could be existing.
I’m looking at completing the repair of the 2465B instrument pre 50,000 S/N. Got started on it about 6 months ago troubleshooting with help from members. Did the repair by replacing the U2460 (original part # NEC D4364C-15LL, replaced with part # NEC D4364C-20L) and replaced the Dallas Keeper battery purchased from Mouser.
That was June 2019. Other things took my interest so just now getting back to calibration. After doing the required calibration I kept getting diagnostic
of test 04 fail 13, Test 04 fail 11, Test 06 fail 01, then back to test 04 fail 01. Couldn’t seem to get ahead of it. So did what I should have done before attempting the calibration and checked the battery voltage. Yea I found it at .6VDC. No wonder I’m dealing with these faults.
So now onto why would the battery be drained in 6 months. The old battery I removed that was from the 1988 vintage was in the same condition so I just thought changing it 6 months ago would allow for another 10 yrs. But that wasn’t the case. So tracing thru the circuit there isn’t anything that I see that would allow for a quick drain of this battery. Feeding two IC, an amplifier, and two caps. Not sure how long it took to drain the battery.

Craig


Re: Tek 222 Probe ground lead

tekscopegroup@...
 

The probes on the 222 are permanently attached to the scope, so I would think it would be difficult to get just a whole probe, unless coming from a parts unit. I just looked at one of the detachable probe ground leads of my 222 and it does not look easy to find an alternative that fits nicely. But if the ground on both probes is common as it probably should be (not sure the fact that the inputs of this scope can be floated up to some serious voltage would change this) maybe you could leave the one ground cable on the ch1 probe and the if you need to use ch2 on the same circuit with ch1 already connected, chances are you would not need the second ground. I hope someone with a parts unit will be able to help you.