[BC] Sick PCL-606C

[radioranger]

Seems to me that there are two or three conditions that must be met for the
transmitter to go into radiate mode, but the likely one here sounds like the
AFC circuit isn't locking up.  If that's the case, there are some air
variable trimmer caps that get "mouldy" (Vince Mercadante's phrase) and just
tweaking the cap back and forth a bit will shake loose the mould and make
things work again, temporarily.

Usually if the filter caps are bad the transmitter will work, but at very
low power output.

Steve B.



>>-----Original Message-----
>>From: broadcast-bounces at radiolists.net [mailto:broadcast-
>>bounces at radiolists.net] On Behalf Of Xmitters at aol.com
>>Sent: Monday, April 28, 2008 9:18 AM
>>To: broadcast at radiolists.net
>>Subject: [BC] Sick PCL-606C
>>
>>
>>
>>Hello:
>>
>>I had to temporarily power down my STL transmitters last night to bypass
>>the
>>UPS. Upon powerup, one of my STL transmitters refused to go back to the
>>Radiate mode. Same problem on the dummy load. The multimeter shows that
>>all of the
>>power supply voltages, but one of the first RF stages (don't remember what
>>it's
>>called ) showed zero. All other RF stages showed Zero. The Radiate/Standby
>>switch made no difference.
>>
>>I've done a great deal of component level troubleshooting and I would like
>>to
>>open this thing up to see what went wrong. I don't want to re-invent the
>>wheel, so I'm wondering if any of you have seen this problem before?
>>
>>Unfortunately, the STL transmitter room is very hot most of the time, as
>>in
>>around 90 to 100 deg F. My guess is that there is probably a bad
>>electrolytic
>>in the system somewhere that's causing the system to go into foldback
>>immediately on power-up, just as a guess.
>>
>>BTW, this PCL-606C is about 10 years old so it's approximately the age of
>>requiring a capacitorectomy :-)
>>
>>All of my other STL transmitters are fine, and we are currently on the air
>>with our backup STL system. No hurry :-)
>>
>>Is there anything specifically that you've seen before that commonly
>>causes
>>these symptoms?
>>
>>Moseley is not open yet, so I'll have to wait to pick their brain on this,
>>and hopefully order out a loaner PC-606C transmitter.
>>
>>Thanks for anything you could suggest that would make the bench
>>troubleshooting chore just a bit more direct to the problem :-)
>>
>>
>>Jeff Glass, BSEE CSRE
>>WNIU WNIJ
>>Northern Illinois University
>>Dell 2650 Win2000 AOL 7.0
>>
>>
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