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Hi Rick. Have you checked the reference oscillator frequency? It doesn’t take much for this to put the entire system out of wack. It’s frequency should be 5.12MHz exactly. This is on the digital

Thanks for the all info Jim, Yes, my TR7 has the fan fitted. 73, Dave

It sounds like the PLL is not locked. Check the VCO voltage. It should be between 4.5 and 7.5 Volts, stable, and move when you turn the main tuning knob. 73 -Jim NU0C "Rick K8EZB"

Thanks, Jim. Yes, lucky for me! I have done some additional troubleshooting. The good news: static power supply regulation seems to be right on on both boards: 13v, 9v, and 5v, all well within Drake

Jim Thank you for your comments. Very helpful. And than you to Dave for raising the topic. I know now the cheap options with mine. Nigel

They all have some small amount of drift. How much depends partly on how well the PTO has aged and the accuracy of the factory temperature compensation. I found that mine have been plenty stable

Lucky for you that I took good pictures of mine. :) As found, set for 7 line. 73 -Jim NU0C "Rick K8EZB" <frboswell@...> wrote:

It bears noting that the original specification for frequency stability for the TR7 is less than 1 kHz during the first hour and less than 150 Hz / hr thereafter. I know that we have all become spoilt

Update: Further testing in accordance with manual checkout procedures indicates a possible digital board issue unrelated to the previously identified freq drift problem. Before I take the

Ken that it does. I get the 1.6mHz offset. Never gave it any thought about 220. The one I’m working on does not have the 220 board. However, the offset board might think it does. Good info mike

Hi Mike, You are getting a 1.6 MHz offset. That is the offset that is normally used on 220 MHz. Is it possible that somehow (don't ask me how) that the crazy thing thinks you are on 220 MHz and gives

Although I promised myself I’d never work on one of these UV3s again… I can’t say that anymore The one I have on my bench has a weird problem with the transmit offset. I set the dial to the

I also recently acquired a loaded TR-7. It came with a German version of a VFO stabilizer, and it keeps the TR-7 within 10Hz from dead cold start. Elcon is making the Elcon 34 frequency stabilizer. I

Hi, New to the forum here. I've had a C line for some time but recently have got a TR7. From switch on, there is a gradual slow drift downwards in frequency of both transmit and receive. During short

Sounds great, Rob! I didn’t change anything with mine other than the scale. Mine said “200uA FS” at the bottom of the scale. I didn’t try calibrating it, as it appears to be showing the

Have progress to share here. Received the meter I bought from eBay. Perfect fit as it was an 83T as the original. The last one available. It was a 0-300 DC Amp. meter. Came with an external resistor

After further review (of the ckt diag and ToO section of the manual, my first guess is voltage regulation of the VCO or VCXO.Basically eveything works, just some slight drift. I'll change over from

Thanks Tom. I chose to log in with google. 73' Sjaak PA3GHL. TRANSLATE with x English Arabic ( #ar ) Hebrew ( #he ) Polish ( #pl ) Bulgarian ( #bg ) Hindi ( #hi ) Portuguese ( #pt ) Catalan ( #ca )

It is starting to sound like this unit suffered from some sort of high voltage event on the control lines. For slow drift I would suspect a problem with one of the voltage regulators or maybe the

Thanks Steve. I have to repair the T4B first. I miss a few tubes and have to clean it and then testing. 73’ Sjaak PA3GHL