Search results

Well that is music to my ears as there is no information on trouble shooting it at all. the voltage charts that are available are not specific to this chip and have contradicting pin outs and voltages between schematics! Also this chip seems to be at an end of life status and only available from...

This ones gonna be a little winded so bear with me. EPT690010C Picked this up for next to nothing previous owner said he was running a palomar 300 amp, amp went kaboom his words next day got the amp out of line fired up the radio no tx had a bad storm that night doesn't know if the amp killed it...

Thanks 399 that's the direction I was heading just wanted a little reassurance on my thoughts before i did it. I've also got some small vr's may just use 1 of them and leave it internal. (out of site out of mind) lol once again Thanks Ira

I need a little information on this mod. Can this mod be preformed without the variable pot to set the dead key at say 2 watts? Maybe a fixed resistor value to set it and forget it kinda like the cobra 29 mod. It's a locales radio and needs to be sorta tamper proof. (nicest way I can say it)...

Just to keep everyone updated I've got the receive working it was both of the 4558 ic's (ic4 and ic301) they work in tandom for the receive, squelch and pa. I was having issues with the tx frequency the 8th 10.240 crystal got me to within 4kz's, ct1 has very limited adjustment and I don't see...

Yes that's the one I've been using there are some differences but close enough for troubleshooting, voltage chart and alignment info would help a lot. Different pll and some difference in tr numbering I can't believe that there's no info on this board is it a hens tooth they only used in one...

Can't find a service manual for this unit. Is there another radio that uses the same board p-200820 or KCMK-47X only numbers I could find on the board. Trouble shooting no receive audio!! What it has tx signal and audio (5kcs low) 3 watt swings to about 18 watt. Has receive signal on meter from...

One other thing, in doing these alignments I always have an issue reading the oscillator frequency on tp6 for the ssb. So I use my hf rig and tune them by ear then get one of my buddies with a waterfall on the radio to come check my signal and fine tune it to spot on. Is there a secret to...

2517 update. It's alive!!! I had aligned the pll section, all good. Then nomads post got me thinking I had 0 watts on the meter but I could see a little signal on the monitor radio with the sniffer hooked up so clipped the sniffer on one of the coils and ran the pa section alignment all pots...

I thought about a 2sa1012 that you use for the sb817 companion since a lot of the sb754 had 1869 as the companion. Any thoughts? Does anyone have a tr/ic voltage chart for this 690011d board. As you know i got the 8 volt up and going did a partial alignment mainly pll alignment everything looks...

Update the puppet master does it again zener was bad now have 8.6 volts on the rail. You da man now I can start checking everything else out. Thank you so much man I love this site. thanks Ira

817,1012 mod regs test good 2003v 5 pin mod amp replaced with a new one lifted all legs on the irf520s removed shorting board then found the issue with the 8 volt rail have tested about half of the electros and ceramic caps working back to the mod regulators.

q35 tested good, haven't pulled the diodes yet I started with the electrolytic caps first but I didn't think the regulator should be 13 volts on the collector when lifted just wanted to verify my starting point was good before continuing. Wasn't sure if the circuit pulls that 13 volts down to 8...

Having issues with the 8 volt rail. It has the sa1869 regulator in it 2.4 volts on the collector when attached lift the leg it goes to 13 volts, removed it tested it on 2 different testers show good no leakage? I've tested components before that showed good when in fact they were faulty! If I...

UPDATE got it straightened out. Well almost had to use vr803 and vr13 to set high and low dead key. Found a few more ceramic caps bad one was on the bottom of the board some missing diodes as well and a few low resistors. All set at 30 watts pep am and ssb Thanks Mike SP5IT for your help...

Yes the power on the front will adjust vr 13 sets the high side vr 16 sets the low side, it supposed to but it doesn't no variable what so ever. Thanks for the link but it's just like the ones I'm using no tr35,39 or 48.

Low Bias driver/finals 2166/2312 x2 No ALC vr#12 No low power adjustment vr#16 I'm trouble shooting these circuits I've came to tr#35, tr#39 (marked tr30 on board, just in front of transformer t1 one voltage labeled this a talk back tr, no talk back in the 2980?) and tr#48. I've been thru the...

hey mike just to let you know the bias was really low on the driver i've got it up some and the ssb dead key is gone. But it still needs more bias thats next. Driver bias .50ma am should be about 75 if memory serves me right. Finals (2) will only come up to 53ma am. ssb driver is .002 finals are...

hey bc just to let you know the bias on the driver was really low i've got it up some and elimanated the ssb dead key. It still needs some more bias so thats next. thanks Ira