ke4zdg wrote:#1 is super high. Sounds like the thermistor (RT501 100K) that senses the heat sink temp is bad. Check for open. Could also be a bad chip. Check U401 and U402.

well i dropped back the power, #1 on meter is reading 39. TPO is about 75 watts. seems to have fixed the pa shutdown issue

#1 is super high. Sounds like the thermistor (RT501 100K) that senses the heat sink temp is bad. Check for open. Could also be a bad chip. Check U401 and U402. I was thinking #1 was a bit high, seems (according to the list from rpt-builder) 40 should be the max. once the weather actually cools off ...

What are your meter voltages doing on the TX jack? See http://www.repeater-builder.com/motorola/msf/msf-metering.html for more info. You may be freaking out the power detection on the PA by bending the frequency down so far. The MSF power regulation compares the output of the IPA to the output of t...

d119 wrote:Stupid question, but have you tried another dummy load?

I have not,

I will be rolling up to the shop today, ill get some fresh meter reads on the tx jack see what i come up with

Are you certain it is thermal shutdown? If the pre-filter / post filter is not aligned right, the high SWR shutdown will cut in. Is this a station that had been working, and is now acting up or is this happening to one you are changing freq on? this is a former base station so no internal pre-post ...

Is there any settings anywhere to adjust the thermal shutdown?

going into dummy load, I can get about a minute or so of TX before it goes into thermal shutdown. PA is cold so no reason for it. and dummy load is fine 1.1/50ohm. I have the triple circ. pa 75w out from the system

Watch out for the PA sense cable connection to the board underneath the RF tray. That's ****ed me more times than I can count. You might also want to take the RF board out of the RF tray and inspect the passthrough connectors. If there's black crud built up around the base of the pins that can also...

can I get bumped over to registered users? been here awhile, don't post much honestly cause well I don't have much to say. but I am a repeater owner and a moto user. maxtrac, gm300 and now MSF5K

well today I took apart everything and got some cleaner and cleaned out every pin, plug, and connector I could. and I now have transmit. PA is working.

I have a UHF CXB R2 5K that I am having some issues with. I have no TX output at all. VCO (both TX/RX locked) on the SSCB the PA on light is off, if i push the xmit switch I get a real fast blink of the PA on, PA key lights. Now I have taken my ft-60r ht and the PA by itself and was able to make out...

1st moto was a maxtrac.

I still have a maxtrac.. course going to have to swap the VHF stuff for UHF

AH HA. http://www.repeater-builder.com/motorola/t1500.html

I have to assume cable length determens the "band split" these things do.

insertion loss kinda makes me frown a bit.. but they will work for now I guess.

I snagged a 4 can rack mount 1504 duplexer set.

!st thing that concerned me was where they was tuned at.. 508/511Mhz

Can I get these down to the 440 band? and how is it done? My Ideal specs would be .5db loss per can and of course 5mhz split.

easy to do, or barking up the wrong tree.

well looking around I nabbed a GE Mastr II 110w UHF machine pretty cheap. with the GE power supply. and some moto t1504a uhf duplexers. wasn't free but worth the price I paid IMO. (shipping is just what killed me)

got to love these chinesse knock offs

Move any manufacturing to China and you WILL be compeating against knock offs. I just dont understand why so many continue to move manufacturing over to china..

the trac going spurious is something that bothers me. Big issue for us with running the maxtrac at full. is duty cycle.. we can keep the machine keyed up for long periods (vhf machine can be keyed for hours strait.) so I was thinking MAYBE it could handle on just the driver.. and using an amp to get...

Hmm, the joys of having to build a repeater with a super small budget eh?

I got a extra maxtrac PA laying over here. might have to give it a shot see if we can produce stable output at 250mW

course still wondering if its even worth the trouble.

Planning a 440 machine. Thinking for the time being using a maxtrac for RX and another maxtrac for and exciter. I can get ahold of some GE Master II PA's pretty cheap. Now the GE's IIRC use about 250mw in the exciters to drive the PA Will it be possible to get a maxtrac down that low? and if I can w...