Recent content by Unit 75

Nomad....That's why I like you. You think outside the box brother. I know something is causing oscillation in the tubes just couldn't put my finger on it. I think you nailed it cause I can honestly say that I can't see anything wrong with this. I'm going to install the shield. P.S. tune control...

That doesn't make sense. That short would be evident as soon as you turned the amp on. If by chance it didnt blow up, it would cause the tubes to red plate from excessive current draw and you definitely would not have full power output. Thank you all for your input. I will continue on with this...

Yes. All electrolytics were replaced 2 weeks ago. They are all 105c caps. If one of the filter caps in the negative grid-bias voltage source failed you would not have full output power from the amp. This has full output.

The problem is audio. Previous owner had the HV supply caps replaced 2 weeks ago. Amp loads and tunes fine with full output power. It has proper biasing and the plate choke is in good shape so there should be no feedback into the HV supply. The amp is being driven by a Cobra 148GTL, which should...

Does anybody happen to have a schematic for this amplifier? I searched the net and can't seem to find one. Thank you in advance.

Thank you Nomad. I appreciate all your help. You rock buddy!

Awesome guys. Thank you so much for the info. I have the new 468 trimmer (175-680pF) I will install then. Nomad, did you mean to say you can still use the high side (not low side) of the amp with the 2 driver tubes removed?

Had a customer drop this amp off to me saying it just stopped putting power out. He told me it was all re-capped. I found a 22uf 35v cap on the 2X 6KD6 driver board that blew the positive side rubber right out. It was an original that had not been replaced I replaced it with a 22 uf 50v cap. The...

Problem fixed. There was a short in the AWI circuit. All is well. Thanks for all your input. Brandon7861...I did do that and had no readings between chassis ground and DC board ground. I even undid all them 103 caps between the two thinking something was leaking but no.

LC...no connection between chassis and board ground. Nomad......I'm pretty sure it came in that way. I pulled the whole selector/display back out and everything is good. All small diodes were checked on the selector board and all are ok...so no Occam's razor happening here. Also, in my initial...

I had a 2005 Cobra 29LTD classic brought to me.... initially to have the channel display replaced. The original was missing a few of segments. Prior to doing any work I bench tested the radio into my dummy load and it seemed to transmit just fine and on frequency. I replaced the channel display...

Spoke with Tom 002 West Birmingham UK today on 27.205 AM on the flat side. Can't ever recall working a UK station on the AM side....usually SSB...until today.

West Coast was booming in today. So was South America. Spoke with Costa Rica, Trinidad and Aruba all on ch20 AM.

Everyone I talk with is either on ssb or am. So, no. I wont be talking fm.

MFJ and DX Engineering have bailed the Ham fest due to COVID19