Eight Orphaned Rack Mount Receivers: Free to a New Home

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UPDATE:
None fired up completely yet, but found 25VDC capacitors on a 35VDC line and 10VDC caps on the 23VDC line. So, got to go through and count and check; then order new caps. Then I can begin testing. Looks like 3 or 4 caps per unit to be replaced.
No, Anole, no pictures yet. Can not test and shoot pictures at the same time. Shop still below 50 degrees F.!
 
Make sure to use something better than just a General Purpose Series capacitor. I have seen in monitor power supplies, upgrading the capacitors from General Purpose Series almost eliminates the power supply failures. Look for low impedance / ESR type and long life in the series used to replace them. A few cents each more now, but fewer failures in the future.
 
...found 25VDC capacitors on a 35VDC line and 10VDC caps on the 23VDC line.
So, got to go through and count and check; then order new caps.
Looks like 3 or 4 caps per unit to be replaced.
I kinda like the idea of getting them running individually, as you are doing.
As for caps, I generally track down and buy the low ESR Nichicon Japanese capacitors when I work on a computer motherboard.
Some members have reported finding them cheap, but they're worth whatever they cost, if you never have to open the receiver again.

Hard to believe someone actually put lower voltage-rated caps on a higher voltage line.
Probably built up an entire batch of receivers that way.
But having been associated with manufacturing in the past, there are ALL sorts of things that go wrong! ;)
 
As for caps, I generally track down and buy the low ESR Nichicon Japanese capacitors when I work on a computer motherboard.

Not to get off topic, but remember the notorious Dell motherboards on their P4 machines that had the capacitor issue? I still need to rebuild a couple of those...
 
... remember the notorious Dell motherboards on their P4 machines that had the capacitor issue?
I still need to rebuild a couple of those...
Too late. P4's are way obsolete. :eek:
So is my dual Opteron server (two actual CPU chips!) and even my nice Core2duo system. :(
(luckily, both are running fine)

Here's the Bad Capacitor site I remember from the old days.
And here is the Capacitor Plague discussion on Wikipedia.
Technically, Pop just has wrong cap, not necessarily bad ones. ;)
 
8 out of 8 need the same 2! More later.
POP

BTW; I did not "test" them before I lifted the boards and followed traces on one unit. Thus the 23 VDC etc are what is marked on board, not measured.

We understood from the facility POC that only a few of the receivers were out. The local small town technician had been paid a few months ago to repair several. When we learned that this local tech was charing the facility $125 each to repair, we pulled a plug on that scam! We sent our own contracted technician to the prison and he pulled these without testing and replaced with GEOSATpro DSR-R100b units.

I will be more than willing to give you a few GEOSATpro goodies to offset your repair expenses as these receivers operation was misrepresented in my post! Drop me a PM after you get these up and running.
 
Not to get off topic, but remember the notorious Dell motherboards on their P4 machines that had the capacitor issue? I still need to rebuild a couple of those...

Our radio station has a couple of LCD monitors by Westinghouse. One of them started taking 3, then 4, then 6, 8, 10, got up to TWENTY cycles of power on/off before it would start up. It was bad caps. Found by a friend of mine more versed in electronics, and much more versed in patience. Replaced all, got a "like new" happy monitor. We wondered if it was the infamous "made overseas" caps causing this! What's really sad is, without his help I would have thrown that monitor out, wasting an item that time and a few bucks actually FIXED. God bless electronics people with patience.
 
IF there's nothing wrong but those caps, then the repairs will be super easy!
We should all be so lucky.
If bad caps have shorted and blown up rectifiers or regulators, then fixing one will probably still be the blueprint for fixing 'em all.
I thought there were various random failures, so any way you slice it, this is still good news. :)
 
Brian,
I did NOT test the units before examining them. The price is right, and this is about what I expected. Two and 1/2 years of building power supplies for United Control, which later became Sundstrand Data, makes me look at these things with a more critical eye. The cost of even 30 capacitors is less than the value of ONE working receiver.
Changing "future failing" caps will keep the total repair costs down. Only 3 caps have TESTED bad (more are leaking and / or bulged) so far no other parts seem to be bad. New caps, then power up.
I know, NO bodies life depends on these supplies like it did while building eq for the air force and nasa (I have breathing equipment parts sitting on the moon!) Landing a C-141 and blow a power supply just before Flare?..... Or have the RGA computer PS fail just after you hit the button? I PRAY not. But this is one thing I still try to do right.

So thanks again. I expected this kind of possibility and so I opened the first one. I am sure it was the failure! It might have blown up if I had powered it up.
And just as a side note, remember the campus radio station Paul Crouch of TBN talks about? I arrived on campus the DAY the main power supply for the station literally blew up - I had it back on line before dark! I had all the parts needed in my footlocker! ----And that was after a 56 hour bus ride... God KNOWS what is going on.
 
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