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Replace the 5.6 volt zener diode and also the associated switching transistor, it is for going between the clock and freq counter. Then replace the electrolytic caps that filter the DC supply and the small one that powers the oscillator / timer.When it goes bad, or shorts, due to bad...

Well the good news, is that most of time time it is simple chinese engineering mistakes, or lack of using proper components and quality control...normally it's a combination of all three. I have spoken so many times to the guys down in San Diego, and their response is always the same.... we have...

Ok see.... it helped. Now that we have some trust, given that the advice was correct...please do the rest. Now that you replaced the capacitor, and touched up some solder joints around the VCO (yes, VCO,voltage controlled oscillator, not VFO) REPLACE the 10.240Mhz crystal. The advice I gave...

People pay that much? I could get a nice Heil for that amount. Thanks for the info though.

I used to have a 575M6 back in the day, but I thought they were discontinued. Buying a used mic just doesn't appeal to me. Is there a source for them?

Ok here's the deal. Repaired many of them, tested many of them with radios for customers on the bench, wired them to radios etc. So I am familiar with this mic. (Astatic Road Devil). However, what interests me, is that most of the mics out there are of the dynamic type. Believe it or not most...

One more suggestion, if you're using it on SSB, make sure your ALC in your radio is intact, and not cranked up all the way. This will keep your average power in check. Also, if on AM, keep the carrier level reasonable, (read: low) and don't overmodulate. The reason I mention this is sweep tubes...

Joker, behind the scenes, the parts you are referring to are coming from China.... so I am confused??

Replace the 1000uf capacitor that goes off of the 8+ volt regulator. Also check and replace the 10.240Mhz crystal. Also, touch up solder joints in the area of the VCO as well. Do this, and it will fix it.

Just leave it alone...monkeying with the AMC until the meter swings all the way to the right isn't going to get you out any better. They come from the factory adjusted very close to correct in this chassis.

Depends, sometimes on small sweep tube amplifiers like this, you could get away with using FINE sand paper and doing that the other people have suggested. However, I don't recommend it. Once they arc, they have a pitted surface and will do it again. If you sand it down, the surface is still not...

To the PS part by shockwave: This is true, and is a poor design, although Dentron and some others actually did this too. Even some of the older Gonset amplifiers would do this, although they did have a terminal on the back for the bias, and assumed you would use it and connect it. But, what...

"If it don't make the same line on the transistor curve tracer to match the original with voltage breakdown or many of the other specifications, it's not a new drop in replacement. It's an old part with a recycled number to maximize profits dishonestly. It's about time we start calling these...

I *AM NOT* advertising, or teying to sell anything. Let me start off by saying that. I am only here to share information. When we used to do this mod to the amplifiers, we would charge 80.00 for the 4 or 5 transistor amplifiers, although on the 667 we really would push customers to just allow us...

Thank you for the "job well done" and also all of your suggestions and input. I really do appreciate it...VERY much! Maybe next is a write up on how to do everything, step by step, section by section. I don't mind doing this, the only problem, is that when I have done this in the past...

One more thing, on a side note, that got me "fired up" about this whole subject, is that I recently had a conversation with a couple folks down there at texas star / galaxy / RCI and brought several design flaws to their attention, such as small changes in the amps, and receiver issues as well...

And to think we haven't even *touched* the subject of the unregulated bias that goes all over the place when excitation (drive) is applied at the base of the transistors. A bias source, needs to be a stable, low impedance source, and be capable of the current required. We can still go...

" Oscillations can drive the input and output VSWR well into the red." Agreed... for a few reasons, one is it can throw the input SWR all over the place, and even damage the exciter by feeding some weird, high power frequency that is unknown back into it. I have seen that happen before...

Getting to all of that in the next post... like I said, we're handling one thing at a time. But remember, even after the chokes, you have RF bypass caps, and also the wirewound resistors are inductive, and act as chokes themselves. Also, I want to make it very clear by what I meant, I think...

It's just the way the computer recognizes the device. But yes, the radio is not using the same circuitry as a lot of the exports use. It is a different animal, and more thought was put into its design, while still haveing the layout, and extra functions available to appeal to the CB / Export market.