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kc8prn (Unregistered Guest)
Posted on Wednesday, March 20, 2013 - 05:15 pm:   

I would love to get one in PDF or other computer format.

Does anyone know if this is a dream or might there be one??

d;-)
Don
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Pete Rossi - WA3NNA (Unregistered Guest)
Posted on Wednesday, March 20, 2013 - 05:34 pm:   

I just found this site.

I have a million questions about the 500 series.. Where to begin..

One that has bothered me.. On the front of the UHF transmitter on
the upper right side, above the power level adjust pot.. to the right
of the antenna relay.. there is a small circuit board with a reed
relay on it. There are 4 wires that run to behind the panel.

What is this for? I tried tracing the wires and all I can find is
they seem to go to the power connect plug.. and do not really tie
into anything in the actual transmitter.

I just spent the last few days going over a UHF transmitter after
a power supply failure last week. One of the filter caps in the
HV supply decided to short. Prior to that, this repeater had
been in operation at it's current site for 10 years with very little
maintenance. This stuff seems to just run.. and run.. and run...

---

Pete Rossi - WA3NNA
wa3nna@pjrnet.com
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Sharcnetusa
Username: Sharcnetusa

Registered: 12-2008
Posted on Wednesday, March 20, 2013 - 05:36 pm:   

Hi Pete,

The board you are referring to is called the "Relay Module".
RCA states its purpose is this:

"This module is used in the keying circuit when extra current switching capacity is required. (For example, it is used between the Quiet Channel keying output and the transmitter relays). When the keying voltage is applied to pin 3, Q1 conducts, energizing K1. This relay connects +12V to the keying line. CR1 & CR2 protect the relay contact from voltage surges"

I have a schematic & assembly drawing I can scan if you need it.

In the QC Module, there is a PNP transistor that conducts and keys +12VDC to the transmitter, which energizes the Transmit/Receive RF relay. The board is like a buffer that takes the same input signal and key an onboard relay that you can use to power somthing else, like a fan, etc. The transistor in the QC module can only supply so much current, so having this board allows you to key other +12VDC devices without burning up the transistor in QC module. Its not required if you don't need to key any other device by +12VDC.
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Bill N8UHN (Unregistered Guest)
Posted From: 10.240.151.209
Posted on Sunday, April 27, 2014 - 10:24 pm:   

I am glad i found this site - it's been very useful.
i just got an rca 500 series uhf rptr.
after a check for bad wires and other safety checks, i powered it up and it did nothing!
i jumped the f1 jumper in the rcvr and the rcvr came up when transmitted to but no xmtr.
i remembered this post about the reed relay board in the xmtr and sure enough the transistor was bad!
after replacing it the tx relays and lamps work but i only have .1 watt out of the exciter and 1 watt out of the pa. the rptr has 5 ctcss modules in it that respond to their tones and the rx and tx freqs check ok on the freq counter with the labels on the txco's. the 3 min timer,driver and hang time are working. tracing the wires in the Control Termination Panel and checking with the 400 series doc's on the repeater builder site seems to line up ok (the rptr wiring is not in the 400 doc's.) i did have to trace the wiring to the latching relay socket in the crtl panel as their is no latching relay in the socket and jumping the f1 lines did nothing with the rcvr f1 jumper removed. there are three wires plugged into the f2 switch pin's that are not in the 400 manual. i still cannot figure out why i had to reinstall the f1 jumper and why no where near the 80w out the rptr is supposed to have - what am i missing?
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Bill N8UHN (Unregistered Guest)
Posted From: 10.240.151.209
Posted on Sunday, May 04, 2014 - 12:17 am:   

Update: I may have a bad tube.
the voltages on the power supply all check ok.
i checked the output of the brick driver module by unsoldering the brick's output lead at the tube and temp soldering a so259 chassi mount socket to it.
the brick is putting out 3w into a 50 ohm dummy load.
that should be enough drive to the tube so i suspect the tube is bad.
still cannot figure out why i had to solder the F1 jumper back together on the rcvr board to get F1 to select - the F1 and F2 buttons work on the ctrl panel now.
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Bill N8UHN (Unregistered Guest)
Posted From: 10.240.148.133
Posted on Sunday, May 11, 2014 - 04:47 am:   

New 8072 tube arrived. installed tube and still no power out. measured plate voltage at tube anode and found no plate voltage. traced wiring to a bad (burned).5 ohm 2% resistor on the board in the lower left rear of pa unit. resistor is a metering shunt inline with plate voltage supply. replaced resistor and got 10w out. tuned pa and got 55 watts out of the duplexer.
put in old tube and retuned pa deck and got 40 w out of the duplexer, so i put the new tube back in. i noticed aprox. 10w duplexer loss.
note: screen voltage is measured at the socket to chassi ground with transmitter keyed.
the rca uhf 500 series repeater is now working.
it is currently on a business band pair and i may rechannel it to the uhf ham band. till then it turned out to be a great addition to my collection.

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