71 radio not working

[Vincent F.]

Re: 71 radio not working

great info, this post really got some wheels turning, I still dont know how to trouble shoot this, I'm going to send it out .

[Dan D.]

Re: 71 radio not working

Oh Vince, Jerry and I really got into it. Send it to Jerry, I don't think you will be disappointed. -Dan-

[Jerry R.]

Re: 71 radio not working

Dan, I thought you were heading off to visit Santa so I was saving comments. :-) It gets harder to browse the forums regularly due to the radio work but I try to skim back a day or two on Sundays. If I miss something you've asked, ping me with an email please.

Just a short note here and then we can look for another thread to steal after the holidays. GRIN Probably the previous C1 antenna related one would be appropriate.

I took lots of measurements of the 54 screen size, etc. and if I remember correctly, there was no series cap in the GC cable. I do remember that after setting the trim cap to resonance with the mesh, I swapped it for a 36" length of wire and it was still close. Also, if the shield ground at the rear (behind the seat) was lifted, signal strengths improved. That's wonderful but I'd put $0.50 on an increase in spark plug noise. Since there was no engine available, that wasn't confirmed.

The chrome will be back for this 55 radio in the next couple days so when I finish it up I'll document anything about the GC cable I used and how I made a correct antenna end connector for it. Most everything is already written down here somewhere but I'll double check before it's gone. I do have many pictures of the modified antenna connector end and the special TNC I robbed parts from to make things.

Snow in NY? Ah yes, that's why I left - not that I had forgotten. Being neive I bought an all electric home there and quickly discovered the finer attributes of wood splitting (and bought several acres around us in Oneonta as a source). Healthiest time of my life. Wish you hadn't mentioned that white stuff. It's so nice down here to be able to drive all year though. And with the big block, I just leave the window open and am quite comfortable. You didn't need to hear that did you! So grab your splitting maul Dan and start swinging. In 10 minutes you'll be warm as toast.

Holler if you need any Caddy radio parts. I still have a few left here for Wonderbar's. The only hard to fix part is that plastic paddle wheel governor when the hub splits.

Regarding the precip static, yes it was real and guys in the southwest would be good candidates to question. As the charge would build, an audible tone could be heard rising in pitch and eventually a snapping sound occurred during the discharge. It was quite noticeable on the 9' steel whips in the children's band days, since those detectors were also AM. (Fixing CB sets sure helped with college costs!) I remember replacing quite a few early 27 MHz FETs as the 1st stage pre-amps would open occasionally but once back to back diodes were added internally in those devices and MOS was developed, I suppose that was the end of that situation and I'm only guessing discharges were the cause in the first place.

Anyway, to shorten this, if my earlier comment about the cable was correct, the 53-55 had no cap so no problem. But even the later C1's used an input coil that was end grounded and since tubes are forgiving, not much damage is/was going to be done. Worst case is that the bias would be thrown off and a little bit of de-sense would be created. You do have it nailed on the cap though. If it's supposed to there and it's not, forget about passing your Wonderbar PV. Finally, it takes about 20 pf to re-resonate when RG-59 is present.

Chat with you after the holidays! Try not to shiver in the mean time...