Date   
My 2465B has arrived + A5 Board leaky caps cleanup

tekscopegroup@...
 

This is a 2465B Sn 55K purchased off ebay, very good external cosmetics, almost pristine interior with only very few traces of dust and so far have not seen any signs of having been disturbed or repaired in the past. Seller was stating that a Test 05 Fail 40 error was coming up upon power up, and that the traces where showing a lot of vertical jitter and eventually would move off screen towards the bottom. I figured that price and shipping cost numbers where decent for a B version, with the front cover and storage pouch (<$250), given the description, which I figured could be related to the well known leaky caps problem, so went for it and won. Oh and somehow the blue filter was loose and almost fell out when I took off the front cover. Have to check the manual, but I figure the filter just needs to snapped back into the groves that seem to hold it in place? If it is so easy to fall off, no wonder so many scopes are being offered without the blue filter, gone missing.

But today upon arrival when I powered up the scope it does not show a trace at all, or even a readout, nothing at all on screen, so not sure how long ago it still had a live screen. The power up self test does stop at the "ADD" label, so as I understand this seems to match the reported Test 05 scenario error. In any case pulled out the A5 board and got started on the leaky cap mess cleanup following some very good suggestions from Chuck not to try to desolder the caps in one piece, but rather carefully chop them up to get to the pads. Well, I kind of cheated and very carefully lifted the single cap in the corner by desoldering it bit by bit by extremely gently rocking it side by side very little at a time while heating the (cleaned up) pads, as it looked easy to do it on that location. It came out fine. But then decided to heed the recommendations as the other remaining 3 caps looked more difficult to get at due to less space around them. I think in the end all went quite well, there was not too much corrosion damage on the pads, and I could not see any traces that where eaten away.

Off course still quite a few other affected parts with dull/greenish pads that will need to be cleaned or replaced (see pictures liked bellow), and I am guessing that in the case of the IC legs that show corrosion they will have to be cleaned thoroughly. Also once I am done removing the rest of the affected SMD resistors and caps, will wash both the affected areas of the board with dish soap and water with a soft toothbrush. Then its into the oven at 375 deg for 45 minutes. Just kidding... its really only 40 minutes that are needed.

Some A5 pictures here:
https://groups.io/g/TekScopes/album?id=76874

BTW the scope has a TEK U800 (not the less desirable Maxim part), and most ICs show a 1990 date code. The NVRam has a 9020 date code. Once I can sort out the most pressing issues with the inoperative display I'm thinking of going the FM16W08 route, to do away with the need of a backup battery for good. I only hope getting the A5 board back in shape will bring back the screen to life. If not once I'm done with it will start checking voltage rails at J119 as well.

Comments and suggestions very welcomed about any follow up tests to make sure I have possibly not missed anything on the A5 cleanup, any know suspect VIAs to check, or hidden traces to verify they have continuity to another part, etc. Any other obvious possibilities besides the A5 mess on why the screen is non-op?

BTW, noticed that one of the 3 caps had two very fine traces between the pads to which the cap is mounted. I see these traces on one side go to what looks like two test points, but on the other side they seem to end nowhere, and don't seem to be connected to the capacitor pads either. Out of curiosity, anyone know what they are meant for? Thanks for any input.

Alex

Tektronix 067-0625-00 Peak to Peak Detector Battery

Craig Cramb
 

Anyone had to locate replacement batteries for this unit. Only marking on the battery is 1A.
Original Tektronix description is: 1.5V, 650MAH, Alkaline-Manganese Dioxide
Tektronix 067-0625-00 Peak to Peak Detector Battery
Pictures on link with dimensions required.

https://groups.io/g/TekScopes/album?id=76872

Re: Anyone have a 5.5 to 18PF variable ceramic trimmer they would like to sell

Brendan
 

On Thu, Oct 25, 2018 at 03:53 PM, Raymond Domp Frank wrote:


On Thu, Oct 25, 2018 at 11:59 PM, lop pol wrote:


Its the trimmer for the A ramp 10us timing :/ am I going to run into issues
trying to use a ceramic trimmer there compared to air?
No issues to be expected at the frequencies involved. Any good-quality trimmer
should do but you may prefer the looks and fit of an original...... As
promised, I'll have a look on Tuesday but please, send me a PM if you haven't
heard until 20.00 GMT.
If I'd have to send one from NL, shipment may be expensive, although it may be
sent as a letter. Where would I have to send it to?

Raymond
Thanks for all the replies. The one in this link https://www.surplussales.com/Variables/Ceramic/CerCap3.html posted by Gary looks amazingly close. I'm going to see what else they have and make an order from them. Looks like an awesome site. Thank you for that. What I'm going to do it get the scope up and running with the trimmers that will be here tomorrow and then when the one from surplussales gets here I will put it in and calibrate the monster. Thanks guys.

Re: Anyone have a 5.5 to 18PF variable ceramic trimmer they would like to sell

 

On Thu, Oct 25, 2018 at 11:59 PM, lop pol wrote:


Its the trimmer for the A ramp 10us timing :/ am I going to run into issues
trying to use a ceramic trimmer there compared to air?
No issues to be expected at the frequencies involved. Any good-quality trimmer should do but you may prefer the looks and fit of an original...... As promised, I'll have a look on Tuesday but please, send me a PM if you haven't heard until 20.00 GMT.
If I'd have to send one from NL, shipment may be expensive, although it may be sent as a letter. Where would I have to send it to?

Raymond

Re: Anyone have a 5.5 to 18PF variable ceramic trimmer they would like to sell

Gary Appel
 

-----Original Message-----
From: Raymond Domp Frank
Sent: Thursday, October 25, 2018 9:59 AM
To: TekScopes@groups.io
Subject: Re: [TekScopes] Anyone have a 5.5 to 18PF variable ceramic trimmer they would like to sell

On Thu, Oct 25, 2018 at 03:14 AM, lop pol wrote:
Hi Lop Pol,

Re: Anyone have a 5.5 to 18PF variable ceramic trimmer they would like to sell



I added a photo of the capacitor. Just in case.

https://groups.io/g/TekScopes/photo/76822/0?p=Name,,,20,1,0,0

Re: Anyone have a 5.5 to 18PF variable ceramic trimmer they would like to sell

Brendan
 

On Thu, Oct 25, 2018 at 02:45 PM, Michael A. Terrell wrote:


I recently bought one of these assortments to get several different values for
a project. I haven't used any of them, so far:

https://www.ebay.com/itm/112638729469?epid=5003063441

Honbay-30pcs-6mm-Plastic-Cover-Trimmer-Variable-Capacitance-5PF-10PF-20PF-30PF/

Michael A. Terrell


-----Original Message-----
From: Raymond Domp Frank <@Raymond>
Sent: Oct 25, 2018 3:59 PM
To: TekScopes@groups.io
Subject: Re: [TekScopes] Anyone have a 5.5 to 18PF variable ceramic trimmer
they would like to sell

On Thu, Oct 25, 2018 at 03:14 AM, lop pol wrote:
Hi Lop Pol,

Re: Anyone have a 5.5 to 18PF variable ceramic trimmer they would like to
sell



I added a photo of the capacitor. Just in case.

https://groups.io/g/TekScopes/photo/76822/0?p=Name,,,20,1,0,0
Quite likely I have one NOS, possibly original. Cost is shipping from
Netherlands. To be certain, please tell me which cap (C...) on which board.

Raymond


Looking at the part number it looks like its an air dielectric trimmer. Its the trimmer for the A ramp 10us timing :/ am I going to run into issues trying to use a ceramic trimmer there compared to air? The one I have coming from Tedss is a Vishay film dielectric . I just hope someone here has a NOS or used OS. One of the ones on they way will at least work until I can get a better suited replacement.. I hope. One member here is going to look at what he has on Tuesday.

Re: Anyone have a 5.5 to 18PF variable ceramic trimmer they would like to sell

Michael A. Terrell
 

I recently bought one of these assortments to get several different values for a project. I haven't used any of them, so far:

https://www.ebay.com/itm/112638729469?epid=5003063441

Honbay-30pcs-6mm-Plastic-Cover-Trimmer-Variable-Capacitance-5PF-10PF-20PF-30PF/

Michael A. Terrell

-----Original Message-----
From: Raymond Domp Frank <@Raymond>
Sent: Oct 25, 2018 3:59 PM
To: TekScopes@groups.io
Subject: Re: [TekScopes] Anyone have a 5.5 to 18PF variable ceramic trimmer they would like to sell

On Thu, Oct 25, 2018 at 03:14 AM, lop pol wrote:
Hi Lop Pol,

Re: Anyone have a 5.5 to 18PF variable ceramic trimmer they would like to sell



I added a photo of the capacitor. Just in case.

https://groups.io/g/TekScopes/photo/76822/0?p=Name,,,20,1,0,0
Quite likely I have one NOS, possibly original. Cost is shipping from Netherlands. To be certain, please tell me which cap (C...) on which board.

Raymond


Re: Type G plugin versions

Dave Wise
 

I was partly wrong. Tek retooled the front panel for BNC, but not until 1967. From 1963 through 1966, they used the UHF front panel with a square-flange BNC jack and plastic trim covering the annular gap. The letter-series plugins built this way are CA, D, G, and L. Others like the K were retooled immediately, if the catalogs are right.

I have plugins of each construction. One of my scopes, a 545, was definitely field-modded, since it was built in the 1950's. It doesn't have the trim and it looks a bit awkward without it.

Beaverton 535A switched to BNC at 31260, but that doesn't tell us anything about Guernsey.

Dave Wise
________________________________________
From: TekScopes@groups.io <TekScopes@groups.io> on behalf of cmjones01 <chris@...>
Sent: Thursday, October 25, 2018 1:27 PM
To: TekScopes@groups.io
Subject: Re: [TekScopes] Type G plugin versions

On Thu, Oct 25, 2018 at 12:44 PM, Albert Otten wrote:
According to the later manual Type G switched from UHF (131-012) to BNC
(131-277) at S/N 9480. No idea in which year that was.
My 535A and G are Guernsey-built. The 535A is s/n 101936, and the G is s/n 101127. They both have BNCs which look like they were factory-fitted, though they are of the special Tek type with enlarged flanges to fit the UHF connector hole.

Chris

Re: Type G plugin versions

cmjones01
 

On Thu, Oct 25, 2018 at 12:44 PM, Albert Otten wrote:
According to the later manual Type G switched from UHF (131-012) to BNC
(131-277) at S/N 9480. No idea in which year that was.
My 535A and G are Guernsey-built. The 535A is s/n 101936, and the G is s/n 101127. They both have BNCs which look like they were factory-fitted, though they are of the special Tek type with enlarged flanges to fit the UHF connector hole.

Chris

Re: Anyone have a 5.5 to 18PF variable ceramic trimmer they would like to sell

 

On Thu, Oct 25, 2018 at 10:05 PM, lop pol wrote:


The cap is C120 on the A13 board so its A13C120. Thanks for looking.
Just realized yours is a 468. It's probably the same as the equivalent cap in a 465(B). I'll be in the lab coming Tuesday and have a look, possibly take a few pictures. I can't imagine the "rotated-by-90 degrees same-function cap" in both models being different. The physical location definitely is but they both are the lying-down variety.
Please send me a PM on Tuesday as a reminder and we'll take our communication off-group.

Raymond

Re: Anyone have a 5.5 to 18PF variable ceramic trimmer they would like to sell

Brendan
 

On Thu, Oct 25, 2018 at 12:59 PM, Raymond Domp Frank wrote:


On Thu, Oct 25, 2018 at 03:14 AM, lop pol wrote:
Hi Lop Pol,

Re: Anyone have a 5.5 to 18PF variable ceramic trimmer they would like to
sell



I added a photo of the capacitor. Just in case.

https://groups.io/g/TekScopes/photo/76822/0?p=Name,,,20,1,0,0
Quite likely I have one NOS, possibly original. Cost is shipping from
Netherlands. To be certain, please tell me which cap (C...) on which board.

Raymond
The cap is C120 on the A13 board so its A13C120. Thanks for looking.

Re: Anyone have a 5.5 to 18PF variable ceramic trimmer they would like to sell

 

On Thu, Oct 25, 2018 at 03:14 AM, lop pol wrote:
Hi Lop Pol,

Re: Anyone have a 5.5 to 18PF variable ceramic trimmer they would like to sell



I added a photo of the capacitor. Just in case.

https://groups.io/g/TekScopes/photo/76822/0?p=Name,,,20,1,0,0
Quite likely I have one NOS, possibly original. Cost is shipping from Netherlands. To be certain, please tell me which cap (C...) on which board.

Raymond

Re: Type G plugin versions

Albert Otten
 

According to the later manual Type G switched from UHF (131-012) to BNC (131-277) at S/N 9480. No idea in which year that was.
Albert

On Thu, Oct 25, 2018 at 08:17 PM, Dave Wise wrote:


I don't know the G serial number at which Tek switched from UHF to BNC*, but
the 1962 catalog shows UHF while 1963 is BNC**. I think I have a newer manual
at home, I'll try to remember to look.

There was a mod kit for converting instruments in the field. I have at least
one modded scope and plugin. Yours too, most likely, as Tek would not have
sold instruments with such an obvious bodge.

Dave Wise

* For what it's worth, the 535A mainframe switched at 31260.
** Some old models were not updated.

Re: Type G plugin versions

Dave Wise
 

I don't know the G serial number at which Tek switched from UHF to BNC*, but the 1962 catalog shows UHF while 1963 is BNC**. I think I have a newer manual at home, I'll try to remember to look.

There was a mod kit for converting instruments in the field. I have at least one modded scope and plugin. Yours too, most likely, as Tek would not have sold instruments with such an obvious bodge.

Dave Wise

* For what it's worth, the 535A mainframe switched at 31260.
** Some old models were not updated.
________________________________________
From: TekScopes@groups.io <TekScopes@groups.io> on behalf of cmjones01 <chris@...>
Sent: Wednesday, October 24, 2018 11:59 AM
To: TekScopes@groups.io
Subject: Re: [TekScopes] Type G plugin versions

On Wed, Oct 24, 2018 at 10:21 AM, Dave Seiter wrote:
My G (serial number just under 10K) has holes in the front panel for the
original connectors, but is loaded with BNCs which look factory installed.
Anyone know when this transition took place?
My G also has BNC connectors. If it's anything like the other 500 series equipment, I think the transition was in the mid-to-late 1960s. My 535A has factory-fitted BNCs as well.

Chris

Re: 2247A PSU Troubleshooting

nielsentelecom@sbcglobal.net
 

Nick,

I have a 2246A that I had to overhaul, which most likely has the identical power supply for your 2247A. I would do a search for the 2246A power supply also here. So I will refer to the component number in your schematic if there is a difference. I wouldn't be concerned with the diodes and caps mentioned in Alex's post until you verify the following.

I also blew up U2201 when I accidentally shorted my scope probe shield against a heatsink while probing. That caused a no power on the main 44VDC bus measured at C2203. even if that is good, I would get a spare replacement. they are not expensive and still available as of a couple years ago.

Get the service manual, refer to page 97, or 3-59, the power supply block diagram, and verify the voltage indicated prior to the preregulator and startup circuit at c2202. that is the main DC bus that feeds the Switching power supply pre-regulator. If you are plugged into 120VAC, it should be at about 160-170VDC. then switch meter to AC, and see if there is any ripple there. That's 120 hz so any meter will work. If that is good then check the previous paragraph for the 44VDC check.

I also was able to test my power supply out of the cabinet. It was risky, but necessary. I used a 10KV AC rated linemans glove and placed the CRT lead inside of it. I also have the resistor values that were close loads for the power supply to operate at a typical load.

NielsenTelecom

Re: Anyone have a 5.5 to 18PF variable ceramic trimmer they would like to sell

 

I run into the same problem many times when restoring radios.

The original trimmers are simply not available

So, I order new modern SMD trimmers from Mouser, and simply solder legs onto them.

Works just fine.

Menahem

Re: Anyone have a 5.5 to 18PF variable ceramic trimmer they would like to sell

Brendan
 

On Wed, Oct 24, 2018 at 05:57 PM, Bill Riches wrote:


Can you send me a pic of the trimmer you need and how much room is there to
mount it?

73

Bill, WA2DVU

-----Original Message-----
From: TekScopes@groups.io <TekScopes@groups.io> On Behalf Of lop pol via
Groups.Io
Sent: Wednesday, October 24, 2018 7:23 PM
To: TekScopes@groups.io
Subject: [TekScopes] Anyone have a 5.5 to 18PF variable ceramic trimmer they
would like to sell

I ordered a 4 to 34PF from jameco but I would like another option. I just
tapped it and I lost the trace on the 468 I'm working on. Good news is I found
a dead transistor on the timing board. Now I have to wait on a trimmer to see
if it fixes my issue.


I added a photo of the capacitor. Just in case.

https://groups.io/g/TekScopes/photo/76822/0?p=Name,,,20,1,0,0

Re: TEK 475 Q1478 2n5859

 

It is not critical.

Re: 2247A PSU Troubleshooting

tekscopegroup@...
 

Hi Nick, can't really give you other troubleshooting tips for a dead 2247A power supply, as I fortunately never had this problem with my own scope, but I hope in the end its something easy to fix. Maybe one of the 22xx series experts here would have some useful tips for you. You mention that you have the schematic, not sure if you actually have the complete service manual as well. If not I would strongly suggest to download a copy which just in case is available on the right hand column on this page:

http://w140.com/tekwiki/wiki/2247

Good luck with the troubleshooting, and don't forget to (hopefully) keep it fun. Also, please report back any progress so the information might possibly be useful for the next person having to go through the same scenario as you are now.

Alex

Re: Anyone have a 5.5 to 18PF variable ceramic trimmer they would like to sell

Bill Riches
 

Can you send me a pic of the trimmer you need and how much room is there to mount it?

73

Bill, WA2DVU

-----Original Message-----
From: TekScopes@groups.io <TekScopes@groups.io> On Behalf Of lop pol via Groups.Io
Sent: Wednesday, October 24, 2018 7:23 PM
To: TekScopes@groups.io
Subject: [TekScopes] Anyone have a 5.5 to 18PF variable ceramic trimmer they would like to sell

I ordered a 4 to 34PF from jameco but I would like another option. I just tapped it and I lost the trace on the 468 I'm working on. Good news is I found a dead transistor on the timing board. Now I have to wait on a trimmer to see if it fixes my issue.