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Recently had a similar issue where the PBT pots on the power supply board were non-functional; problem turned out to be internal PBT switch leakage to the lamp circuit, which was offering a low-z path

Thanks Steve, with your help I may be able to make this Drake R-4B sing again. Steve there are no problems with package delivery in Italy. Poste Italiane are working well. I regularly receive

The passband tuning voltages are steered by quad analog switch IC U1001 on the PBT/Reference board. If the control signals are reaching the IC and it is not switching as it should it has likely

Just making sure: you don’t have the PBT button pushed in, right? BTDT Steve Wedge, W1ES Time flies like an arrow. Fruit flies like a banana. Sent from [Proton Mail](https://proton.me/mail/home) for

Hi everyone. Made great progress, all alignment looked fine until I got to the bandpass tuning pots on the power supply board, moving them all, nothing happened, 10v adjust ok. Took the board out,

I have one but am not sure about what would be involved with shipping. Are there still issues with sending parcels to Italy? Steve Wedge, W1ES Time flies like an arrow. Fruit flies like a banana.

Interesting discussion here ... https://www.eevblog.com/forum/testgear/best-capacitor-tester/

Thanks for the tip! I will try this as soon as I can get the replacement resistors installed. I do have a nice scope. 73, Dave KD5FX

Actually T-7C reduces the noise bandwidth of the third mixer. It doesn’t change the gain. Rob, NC0B

I have one of those little testers.? Capacitor checks seem to be close to what my much older Sencore LC75 meter shows.?? The Sencore meter will check leakage at various voltages. Not able to do

Matteo, you are not crazy but you must be determined. The distortion tells me something is amiss with the AGC system -- incorrect AGC voltage or bad interstage coupling caps putting B+ on the grids.

Received the caps and an ESR tester. So far, so good ... See attached pic.

Good morning friends of the Drake group. I have been given a faulty rx R-4B as a gift. I overhauled the power supply part which was found to be faulty. The radio now turns on receives its internal

I did not find any ‘4427’s. I’ll find the spreadsheet later as I have an appointment to make at the moment. Steve Wedge, W1ES Time flies like an arrow. Fruit flies like a banana. Sent from

The 2n4427 has unique properties, not easily substituted. Jim WA9Z Exline IA Possibly 2N5109 as a viable substitute. Not easily found these days but here’s one source:

That number looks familiar. I’ve been meaning to post my spreadsheet of available transistors that I sorted from a tacklebox full of randomly-mixed parts. I will try and remember to do this shortly.

Thank you Jim for that bit of information. ,I replaced the transistor a few years ago working on it but just got around to working on it again. Regards, Jim [email protected]> wrote:

Probably a good idea if you have questions about something else in this set :-) 73, Steve Wedge, W1ES Time flies like an arrow. Fruit flies like a banana. Sent from [Proton

Our records show having replaced a few of these over the years.? BM and the buffer.? Almost sounds like it qualifies for common failure analysis. The 2n4427 has unique properties, not easily

Yes, can cap was already replaced before I got this radio. He didn't put a new can style in it, he used individual caps. This tread is very long now. The original problem is solved with the baked