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looking for 5500 uf cap for tek 475
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jeff corey
I picked up a dead Tektronix 475 that lights up but no display for a project and am going thru it. Starting of course with the power supplies I noticed there is not straight DC coming off Q1448, but see a waveform with an ac component on the 15v line. so I am thinking the big 5500 uf cap is open or really leaky. Seems like this part goes out a lot as nobody seems to have them on the interwebs, all sold out. it is tek part number 290-0584-00 . anybody have any to sell? hard to believe a capacitor like that is unavailable.
Jeff WB9KAZ
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Use a radial 6800 uF 50 volt or so cap. Modern electrolytics are smaller than the old ones. The exact values are not critical.
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On 6/1/2020 8:23 PM, jeff corey wrote:
I picked up a dead Tektronix 475 that lights up but no display for a project and am going thru it. Starting of course with the power supplies I noticed there is not straight DC coming off Q1448, but see a waveform with an ac component on the 15v line. so I am thinking the big 5500 uf cap is open or really leaky. Seems like this part goes out a lot as nobody seems to have them on the interwebs, all sold out. it is tek part number 290-0584-00 . anybody have any to sell? hard to believe a capacitor like that is unavailable. --
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Also, remember there is track on both sides of the board and the three negative can contacts are a part of the circuit. Just use a jumper to tie the ground points together. A CLOSE INSPECTION OF THE BOARD AFTER YOU HAVE REMOVED THE BAD CAP IS NECESSARY!
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On 6/2/2020 1:56 AM, Tom Miller wrote:
Use a radial 6800 uF 50 volt or so cap. Modern electrolytics are smaller than the old ones. The exact values are not critical. --
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Paul Amaranth
There was a short discussion on this just the other week. You can
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get (or make) small pcbs that adapt a standard snapcap to the 4 pin footprint of those cans. You can get them on ebay for a buck or so apiece. Makes for a nice repair. You do need to jumper the 3 ground pads one way or another. Those metal cans haven't been made for years. Paul
On Tue, Jun 02, 2020 at 01:56:36AM -0400, Tom Miller wrote:
Use a radial 6800 uF 50 volt or so cap. Modern electrolytics are smaller --
Paul Amaranth, GCIH | Manchester MI, USA Aurora Group of Michigan, LLC | Security, Systems & Software paul@AuroraGrp.Com | Unix/Linux - We don't do windows
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n4buq
I was thinking those adapter PCBs make those ground pad connections. I have some in the shop and can check but I thought they did.
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Thanks, Barry - N4BUQ
----- Original Message -----
From: "Paul Amaranth" <paul@auroragrp.com>
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Brian Bloom
The adapter PCB's do make the ground connections, I have some and have used some. Someone, I forget who (sorry!!) designed ones for the "small" cans that are in 465, 466, 475, etc. and ones for the "large" can caps that are in 7K series mainframes and shared the gerber files, which I do have and can email you. I've also seen other ones up for sale on ebay if you want to get them faster. Additionally, if you go to oshpark site and search the shared for "DM103R2" there is yet another design for the capboard you need. They make for a nice clean looking repair job.
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Barry Wrote:Barry, That is correct, they do make the ground connection. -- Michael Lynch Dardanelle, Arkansas
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jeff corey
Wow, thanks to all for your prompt responses! I found the adapter boards on fleebay and will order some and re-cap the 5 caps in the PS with newer technology. I have been away from my roots as a EE running a sucessfull IT company that pays more, but with quarantine and all i have had more time and interest in repairing old equipment. Component technology has sure changed since the big can capacitors we designed into the 48 v power suplies at the ITT phone company where I started. I remember a tech soldered one in backwards and I was up on a ladder debugging some wirewarap backplanes and it narrowly missed my ear as it shot its outer can off like a bullet.
Of course now that I have gotten reinterested in boat anchor tech the Hamfests are a distant memory. Hope they can start up again! Jeff WB9KAZ
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VK1GVC
Jeff, I see you've found them on fleabay but FYI Michael posted about 10 days ago that they were eBay item 273254508468 where I found them too. The cost of a set of boards is USD11 whereas the postage to AUS is about USD19 - hardly a good deal unfortunately. I asked the seller about any less costly postage and he said he was bound by eBay rules to have package tracking, hence the cost. I guess I'll do without.
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Hope your postage costs within CONUS are a bit more reasonable! Graham
On 3/06/2020 12:14 am, jeff corey wrote:
Wow, thanks to all for your prompt responses! I found the adapter boards on fleebay and will order some and re-cap the 5 caps in the PS with newer technology. I have been away from my roots as a EE running a sucessfull IT company that pays more, but with quarantine and all i have had more time and interest in repairing old equipment. Component technology has sure changed since the big can capacitors we designed into the 48 v power suplies at the ITT phone company where I started. I remember a tech soldered one in backwards and I was up on a ladder debugging some wirewarap backplanes and it narrowly missed my ear as it shot its outer can off like a bullet. --
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Harvey White
You might be able to find designs on line (perhaps Seeedstudio?) and have them made in China. Postage to the US is nasty, about what you've already experienced, but to AU? no idea.
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Harvey
On 6/2/2020 10:44 AM, VK1GVC wrote:
Jeff, I see you've found them on fleabay but FYI Michael posted about 10 days ago that they were eBay item 273254508468 where I found them too. The cost of a set of boards is USD11 whereas the postage to AUS is about USD19 - hardly a good deal unfortunately. I asked the seller about any less costly postage and he said he was bound by eBay rules to have package tracking, hence the cost. I guess I'll do without.
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Eric
Osh park has some boards open hardware the price is for 3, I used them in a 576 repair that is on you tube if you would like to see what they look like.
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On 6/2/2020 12:47 PM, Harvey White wrote:
You might be able to find designs on line (perhaps Seeedstudio?) and have them made in China. Postage to the US is nasty, about what you've already experienced, but to AU? no idea.
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Eric
Graham try Oshpark direct from the PCB maker. 11 us for 3 adapters. At least it was not sure what the shipping would be.
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On 6/2/2020 10:44 AM, VK1GVC wrote:
Jeff, I see you've found them on fleabay but FYI Michael posted about 10 days ago that they were eBay item 273254508468 where I found them too. The cost of a set of boards is USD11 whereas the postage to AUS is about USD19 - hardly a good deal unfortunately. I asked the seller about any less costly postage and he said he was bound by eBay rules to have package tracking, hence the cost. I guess I'll do without.
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tek part number 290-0584-00 . anybody have any to sell?
Ebay listing: 133209786060
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It is only an 85°C cap that is already 17 years old.
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On 6/2/2020 7:10 PM, Craig Cramb wrote:
tek part number 290-0584-00 . anybody have any to sell? --
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VK1GVC
Thanks to Harvey and Eric for their suggestions about alternative ways to get hold of the little round PCB adapters for 4-legged capacitor mounts but Jeff contacted me off-list and offered to order some extras from the eBay supplier and post them to me in AUS. If I read the USPS website correctly this should only cost USD2 or 3 and they will lie nice and flat in a letter envelope if stuck to a piece of light cardboard; no need for the awkward shaped headers, just the PCBs.
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Special thanks to Jeff! Graham
On 3/06/2020 9:55 am, Tom Miller wrote:
It is only an 85°C cap that is already 17 years old. --
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