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Have you swapped the 12BY7 driver tube?? I had a problem with erratic bias and an oscillation on higher bands in a TR-3 recently that was resolved with a swap of the driver tube.? The tube tested

Well, this morning it's behaving normally and I was able to set the BIAS with no problems. Strange! I'm hearing lots of stations on 28.0 and 28.5 bands this morning but nothing yet on 29.1. I can hear

Good to hear from another TR4310 user, Jan:-) I reckon I have both sizes of those key here - somewhere! With the synthesiser in the TR4310 now working well (and the VCXO / rubber-crystal alignment

Mark - The EHC knobs were previously Raytheon 70 series, used in a wide range of military equipment. ?I use to buy these at Collins surplus store in 1980s. Surplus Sales of Nebraska has Sold Out of

Yeah, I had a bit of a time trying to find R192 the first time or, actually, finding out the reference designator was of “that burnt resistor on the relay board”. The schematic, if I remember,

The 8-volt version costs quite a bit more than the 6-volt equivalent. As it was a one-and-done replacement for my personal 2-B, I didn’t mind paying the difference. If you do want to save, you can

Hi Steve et al Em 22/01/2025 22:35, Steve Wedge, W1ES/4 via groups.io escreveu: There are two relays. One controls changing over the antenna

Thanks Jim. Yes, I have seen that very good article. Note that there are no series resistors in the base or emitter paths of the final transistors. So I wanted to be very cautious with them. Since I

Interesting discussion. I have never had to dive into the bias circuit for the finals. However it seems to me that you need to think in terms of current rather than voltage. The circuit is clamped by

Working on a project TR7 with/for a friend. I am starting to think we might actually get this back together someday. So it is time to continue the search to replace the missing parts. We need the

Working on the PA brick of a project TR7, it was clear that someone had been concerned about the bias to the finals since Q2305, an EP487 was lifted. Expecting that we would need to replace that, I

I suppose that the 8BN8 would more likely be found in the television repair man's caddy. There are quite a few on eBay right now. "Gary Follett via groups.io" <xntrick1948@...>

Well, it seems to me to make sense to put in the resistor that Hallicrafters used since 6BN8 tubes are far more common than the 8BN8. In fact, I have half a dozen of 6BN8 tubes and zero 8BN8

Congratulations on the crystals. There are two relays. One controls changing over the antenna and mute functions and the other, smaller one changes enabling voltages from receive to transmit. There

The short answer is "no". Unless you like hum in the audio. Longer answer is here: https://www.wb4hfn.com/DRAKE/DrakeArticles/Why_8BN8-2B.htm ...as well as in discussions in this forum. "amfone

EUREKA! IT WORKED! I baked the 28.0 and 28.5 Xtals for 3 hrs today at 350 then let them cool down for an hour or so. Put them in the radio and now I'm hearing signals on both bands! Xmit isn't working

Will do Dave. Jim VE1RB [email protected]> wrote:

Scott, are you attempting to use one TR-4C as a transmitter and another as a receiver such that one can control the other when necessary or desired? The answer is that won't work without some

Hey, Scott, You can’t transceive with a TR-4(any) and an R-4(any) because the two radios use different IF’s and different frequency mixing scheme. The receivers use A 5645 kHz IF, whilst the

Hello! I have a Drake TR4C and R4C receiver, and noticed there are no injection cables available for this setup as there were for the T4XC and R4C twins. I know there is an RCA cable (each) for