Date   

Re: SC502 With Display Issues

Stephen
 

I’ve made quite a mess...
I wanted to check the voltages. I plugged in the extender and forgot to power off the TM, and didn’t insert it correctly. I blew the 2 +/- 35v fuses. Replaced them and now all the plugins work fine except this one. Nothing... No power at all. All the other plugins that stopped working when that happened, are now ok in all bays.
I checked the 2 fuses inside the unit, and they’re good...
BTW, the SC was in the OFF position when that happened.
Grrrr. I shouldn’t be doing these things at 1:00am.

PS: I was planning on replacing all the tantalums anyway, just for good measure.


Re: Looking for front cover for 465 and/or 485

Dave Daniel
 

Most covers were separated from their ‘scope when the company that bought the ‘scope started using it. When the ‘scope was retired, the cover remained in a cabinet or whatever and was later tossed because there was no associated ‘scope with it (or, for all I know there are thousands of ‘scope covers still sitting in cablnets all over the world).

DaveD

On Aug 15, 2020, at 15:23, Roy Thistle <roy.thistle@mail.utoronto.ca> wrote:

On Fri, Aug 14, 2020 at 04:28 PM, John Brown wrote:


The whole world is looking for covers
.... well... I'm out here in the colonies (not in CONUS) ... so if someone has covers for 400 series scopes... out here in the colonies... P.M. me... I'd like to get some.
As an aside... it's odd behaviour, to throw out the oscilloscope; but keep the cover! (Keeping the probes is an annoyance I can contemplate.)



Re: SC502 With Display Issues

DaveH52
 

If you have a service manual, spend the time to read the functional description while following along in the schematics.
My starting point was smoke and lots of it. I'm going to be busy for a while replacing every tantalum capacitor and all of the A1-A5 HV caps because one of them had arced to a wet tantalum that spewed sulfuric acid. Once that was repaired, each power-up after that, would fail because another tantalum cap had failed and burned up a resistor. Therefore, not they're all getting replaced.


Re: 'Soft' transistor sockets

 

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Tim Phillips
Sent: 15 August 2020 21:13
To: TekScopes@groups.io
Subject: Re: [TekScopes] 'Soft' transistor sockets

Hi Egge; no, maybe I didn't explain myself very well - the 'sockets' I
referred to are actually three individual tiny contacts on the PCB into
which the transistor leads go directly. Not an actual socket as we
understand the word ! Imagine a very low-profile socket, but without the
surrounding supporting material, just the contacts.
regards
Tim


On Sat, 15 Aug 2020 at 20:23, Egge Siert <eggeja2@hotmail.nl> wrote:

Hi Tim,

This kind of sockets?


https://www.ebay.com/itm/4-Mil-Spec-S-Augat-8058-1G24-1437508-9-4P-PCB-Mount-Teflon-Transistor-Sockets/201234498862?epid=1236928307&;hash=item2eda82c52e:g:d54AAOSw4gpbyhtN

Greetings,

Egge Siert




Re: Tek 4654M; No Trace, No +5V, No +95V; Help

Chuck Harris
 

Definitely, it is exceedingly rare that you can adjust your way
out of total failure.

-Chuck Harris

Dave Hills wrote:

Hello, Harrison.
I would not adjust anything at this point, as any adjustment can't correct for this much out of spec.
Take a look at the voltages across C741 and C761. Measure both DC and AC values. The DC
voltages should be around 10v or more and the AC voltage much smaller.
Please let us know what you find.

Dave




Re: 'Soft' transistor sockets

Chuck Harris
 

The thinking was:

... transistors are expensive, very variable in their gain
from one example to the next, and we are not so convinced
that they are any more reliable than vacuum tubes. So, we
need sockets for the transistors, ... a lot of sockets...
but the available sockets are so expensive, and take up a
lot of room, and are not all that reliable...

The little insert pin sockets that tektronix used are very,
very reliable, and the silicone gasket at their entrance can
take the heat of soldering, and keeps foreign materials out
of the socket... Plus, it adds a little more resistance to
the transistor falling out of the socket.

Tektronix found over time that transistors got cheaper, and
were much more reliable than any sockets you could use to
mount them, so they went to directly soldering the transistors
into the circuit board.

-Chuck Harris

Tim Phillips wrote:

from Tim P (UK)

What was the thinking behind the 'soft' transistor sockets used by
Tektronix in some of the 5000-series 'scopes? I am working on a 5113 / D13
that has these on the storage board. Seems to be a soft white-ish stuff
around the contacts, and it's not clear (to me) if the transistor is making
a good connection.
Also, the lead spacing on the transistor is very slightly different to the
usual T05, meaning a replacement has to be 'jiggled' into it's socket.

regards
Tim




Re: 'Soft' transistor sockets

Bert Haskins
 

On 8/15/2020 4:12 PM, Tim Phillips wrote:
Hi Egge; no, maybe I didn't explain myself very well - the 'sockets' I
referred to are actually three individual tiny contacts on the PCB into
which the transistor leads go directly. Not an actual socket as we
understand the word ! Imagine a very low-profile socket, but without the
surrounding supporting material, just the contacts.
regards
Tim


On Sat, 15 Aug 2020 at 20:23, Egge Siert <eggeja2@hotmail.nl> wrote:

Hi Tim,

This kind of sockets?


https://www.ebay.com/itm/4-Mil-Spec-S-Augat-8058-1G24-1437508-9-4P-PCB-Mount-Teflon-Transistor-Sockets/201234498862?epid=1236928307&;hash=item2eda82c52e:g:d54AAOSw4gpbyhtN

Greetings,

Egge Siert



I have used these and I like them except for the fact that they are obscenely expensive at least when I have been able to purchase them.

I have ended up pushing the pins out of machined pin IC sockets and using them instead.

There might be some difference at high frequencies but I will never see it.

-- Bert


Re: Oscilloscope Operator Training Kit - TNGTDS01

Roy Thistle
 

On Fri, Aug 14, 2020 at 10:32 AM, ebrucehunter wrote:


TDS3052B digital scope; however, it seems only very distantly related to my
465 that it might ultimately replace
Well... I'd claim the TDS2052B "trace" it is closer to the 465... than many other Tektronix DSO. (You've got the so called digital phosphor.)
Anyway... the signals the "Training 1 Signal Board" put out are described in Appendix A of the document you quoted.
Are you planing to work on modern digital systems? ... because you mention you are/were using a 465.


Re: 'Soft' transistor sockets

Dave Seiter
 

Are these the type that have a sort of rubber grommet at the top that the pin goes through?
-Dave

On Saturday, August 15, 2020, 01:11:20 PM PDT, Tim Phillips <timexucl@gmail.com> wrote:

Hi Egge; no, maybe I didn't explain myself very well - the 'sockets' I
referred to are actually three individual tiny contacts  on the PCB into
which the transistor leads go directly. Not an actual socket as we
understand the word ! Imagine a very low-profile socket, but without the
surrounding supporting material, just the contacts.
regards
Tim


On Sat, 15 Aug 2020 at 20:23, Egge Siert <eggeja2@hotmail.nl> wrote:

Hi Tim,

This kind of sockets?


https://www.ebay.com/itm/4-Mil-Spec-S-Augat-8058-1G24-1437508-9-4P-PCB-Mount-Teflon-Transistor-Sockets/201234498862?epid=1236928307&;hash=item2eda82c52e:g:d54AAOSw4gpbyhtN

Greetings,

Egge Siert




Re: 'Soft' transistor sockets

Stephen
 

This is what you’re referring to:
https://groups.io/g/TekScopes/photo/252113/0?p=Created,,,20,2,0,0


Re: 'Soft' transistor sockets

Tim Phillips
 

Hi Egge; no, maybe I didn't explain myself very well - the 'sockets' I
referred to are actually three individual tiny contacts on the PCB into
which the transistor leads go directly. Not an actual socket as we
understand the word ! Imagine a very low-profile socket, but without the
surrounding supporting material, just the contacts.
regards
Tim

On Sat, 15 Aug 2020 at 20:23, Egge Siert <eggeja2@hotmail.nl> wrote:

Hi Tim,

This kind of sockets?


https://www.ebay.com/itm/4-Mil-Spec-S-Augat-8058-1G24-1437508-9-4P-PCB-Mount-Teflon-Transistor-Sockets/201234498862?epid=1236928307&;hash=item2eda82c52e:g:d54AAOSw4gpbyhtN

Greetings,

Egge Siert




Re: 2465 Fan Collet Thingy

Li Gangyi
 

Alrighty, I've successfully made a couple of these and tested them out (although I don't own the actual fan/scope).

https://groups.io/g/TekScopes/album?id=252111

Threaded and stud added (m4x0.7), I'm not sure of the stock hardware (was it a nylok nut and spring washer for example?). I tested a few to destruction with a 1.8mm shaft (actually an air adapter for filling up basketballs and such) and cranking it down until I heard a crack, all the failures where at the collet, non stripped out. They failed with way more torque that you'd normally put thru such a small nut, although reefing on it would crack it. I have no real means to measure the amount of torque required (the smallest torque wrench I have goes down to only 30inlbs).

If anyone would like a few to try (I'll ship them with a set of hardware), or you want to tap them for your thread size, i can leave the hole unmolested. contact me offline and we'll sort that out.


Re: Looking for front cover for 465 and/or 485

Roy Thistle
 

On Fri, Aug 14, 2020 at 04:28 PM, John Brown wrote:


The whole world is looking for covers
.... well... I'm out here in the colonies (not in CONUS) ... so if someone has covers for 400 series scopes... out here in the colonies... P.M. me... I'd like to get some.
As an aside... it's odd behaviour, to throw out the oscilloscope; but keep the cover! (Keeping the probes is an annoyance I can contemplate.)


Re: 'Soft' transistor sockets

Egge Siert
 


Re: Tek 4654M; No Trace, No +5V, No +95V; Help

Dave Hills
 

Hello, Harrison.
I would not adjust anything at this point, as any adjustment can't correct for this much out of spec.
Take a look at the voltages across C741 and C761. Measure both DC and AC values. The DC
voltages should be around 10v or more and the AC voltage much smaller.
Please let us know what you find.

Dave


'Soft' transistor sockets

Tim Phillips
 

from Tim P (UK)

What was the thinking behind the 'soft' transistor sockets used by
Tektronix in some of the 5000-series 'scopes? I am working on a 5113 / D13
that has these on the storage board. Seems to be a soft white-ish stuff
around the contacts, and it's not clear (to me) if the transistor is making
a good connection.
Also, the lead spacing on the transistor is very slightly different to the
usual T05, meaning a replacement has to be 'jiggled' into it's socket.

regards
Tim


Re: SC502 With Display Issues

teamlarryohio
 

Perzackly! That electric field is what does the deflection when it is the right polarity and magnitude at any given instant. When the voltages at the plates are not correct, neither is the position of the spot that draws the trace. In the extreme, that is often offscreen.


Re: Oscilloscope Operator Training Kit - TNGTDS01

 

Thanks Egge,
I searched eBay for Tek TNGTDS01, but did not think of searching for "Operator Training Kit." 

It also occurred to me that a member of the group might have one of these kits they might be willing to loan, rent, or sell.

Bruce, KG6OJI


Re: Tek 4654M; No Trace, No +5V, No +95V; Help

Harrison
 

Thanks Chuck. I have taken your advice and concentrated on the +5V circuit. Current conditions +32 TP reads 34.1, +5 TP 3.8, -5 TP -4.7 and 95 TP reads 8.8. I have read out all components in the +5 circuit from the +32 feed through R741 and R742 to the jumper before the +5V TP. If I got a good reading in circuit, I went with that. If I did not, I pulled the item from the circuit or lifted one lead and tested it that way. Everything seemed to check out OK except for pin 6 of U722B (FO-10) should read +5 but was reading 0.660, pin 7 should read 6.0 but read 14.71. Because the “power on” LED is not lit when the unit is turned on, I decided to jump over there a bit and read out U2280 on the Trigger board (Figure FO-5). All seemed well there except pin 6 reads -.38 instead of -3.6 and pin & reads -.25 instead of +5V. Now trying to figure if I need to back up more in the system or is the issue coming from somewhere else in the unit. I have no background on this unit. There appears by magic marker markings that some work or alignment has taken place, which is not surprising given the age of the unit. However, I do not see any real hack jobs or obvious internal damage or signs of non pro lab work. I have been trying to raise my electronic theory knowledge and troubleshooting skill on this unit. It came from a Ham fest, was labeled “working” which it clearly was not. Bottom line, while I found a couple of bad readings, I am no closer to solving the issue and getting this unit back online. I did replace CR 582 (Figure FO-9) and Q742 (FO-10) I am not convinced either was bad. My initial TP readings were +32 read +32, -5 read -5.07, +5 read -.752, and 95 read 5.74. My current set of readings is different. I do not know if that is because of the two part replacements, something else or just variation in collection. I did use the same Beckman HD110 meter to take the readings. Because the TP reading are now out of spec should adjustments be made for the respective pots for each circuit? At a loss as to where to go from here. Don’t like throwing in the towel but not sure I am making any meaningful progress at this point. Any advice and ideas, anybody, would be appreciated? Harrison N1FAM


Re: SC502 With Display Issues

Stephen
 

Thank you Larry, Michael and Roger for your explanations and help.
I will report back when I get to it shortly.

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