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Check and see if you have 8 volts at C170, that supply runs all sorts of things in the radio. Jim

I like the look of the radio but: 1) It has the original caps 2) A class C amp 3) An unshielded switching power supply (it must sound worse tha a Galaxy on receive) 4) A user called Bite_Me and #5) "SOLD AS IS PARTS OR REPAIR WITH NO WARRANTY AND NO RETURNS" He should have started it at...

C179 shorts out, it is between the final bias posts and causes the very problem you are talking about. I change it in every 858 radio I work on. use a 2.2uf 50 volt to replace it. Jim

If I remeber correctly this is the same board as the Midland 77-882, I wouldn't waste the 1307.... But if you must, remove Q15 and RV2, R59 should be 1K, R58 should be 27-33K, and C81 should be a .022uf. you can try changing C94 to a 470uf or 680uf cap. These radios don't have a mic preamp...

It looks like TR18 is the final and TR19 is the driver.

130% modulation??? Once the swing kit is installed and you dead key .5 watts and swing up from there, doesn’t the accuracy of a modulation meter suffer? And if it is really 130%, isn’t that just advertising a square wave splatter box radio?

I have done plenty, 457, 458, 449, 138XLR, 139XLR, 858 Madison's, 858 Washingtons, Robyn 520D's, and others. This chassis has lots of channel, TX and RX mods available. The 457 I have right now has been converted to blue clock and channel displays, has the 2sc2999 receive mod, and sounds really...

His isn't even blue......... Mine must be worth THOUSANDS!!!!! :lol:

This is just a President 25GTL. This would be a good start: If you have a volt meter you need to set the radio to Channel 40 receive, find test point 2 and attach the meter between TP2 and ground. Carefully adjust L15 until you see 3 volts at TP2. When the radio is keyed the voltage at TP2...

.38 ohms in the 20K range is fine. Did you get the diode yet?

Looking at the schematic Needle Bender could still be right, Uniden and Cobra used 2 different audio grounding methods at the mic jack. Beyond that, the mic gain is fairly well isolated from the RX audio section. Jim

Sounds like the diode is done, replace with NTE5074A or a 11v 1 watt zener. R314 should read about 380 ohms in circuit so .38 in what range??? If its .38k ohms you are okay, if its .38 ohms the transistor is gone too, that is a 2SD526. If the cap charges up into the meg ohms it should be...

Pull C328 and D244 and see what part is shorted out of circuit. with the 2 parts out you can check the resistance of R314, R315 seems to be passing voltage to the regulator so it may be okay. Jim

You are looking for Q229 (TO220 in the back), you should have 13.8v on the collector, about 9.3v on the emitter, and just under 10v on the base. R314 or R315 off of the collector could be open, C328 could be shorted, or D244 could be shorted. Q229 supplies / links to voltages all over the...

Its funny, for a chassis that is nearing 35 years old they hold up better than anything built in the last 10 or 15 years. Glad to hear it all worked out. Jim

The mode LED's come on or dont come on?

Do you have any kind of hiss from the speaker at all? When you key up can you hear a click from the speaker itself? This one will make you cringe, take a metal screwdriver while the radio is live (RX mode) and very carefully touch pin 4 of the audio IC, do you hear anything? These radios are...

I have had a few of these and I seem to remember replacing the crystal before. I like the look of these radios, even better when they are all blue :thumbup: Jim

With No AM TX audio and no AM/SSB receive audio I would start with the audio IC (UPC1156H). If you have an O-Scope check at pin 4 to be sure you have an input signal, if you do check at pin 10 that is the output. If you don't have a scope it would still be the most likely part, so if you can...

The microphone is most likely wired wrong, you need to get your hands on a realistic wired microphone or re-wire what you have. Jim