RCA stereo TPM12 - 1960

[Motorola minion]

Here is a unit I picked up which looked and sounded great after a routine recap, it sold right away. Despite a photo-finish mahogany cabinet and plastic legs - yes it had appeal! RCA mark down model wins over more expensive provincial models LOL!

My customer had it in his antique booth when it stopped after a blown fuse. I replaced it with a 3 amp slo blow version of the fast-acting 3 amp and got a very cheap fireworks show.

One of the two 16-watt audio-output transformers started smoking and lit up enough flame to light a Lonsdale cigar before I pulled the plug. Fuses blow for a reason, fast acting may blow due to fast-on-off-on cycles due to line fluctuations or monkeying with the power switch. I made that- particular assumption when I changed it, lesson learned. Tubes tested OK on unaffected side but weakened considerably on the affected side.

[William]

Not a bad looking unit and it has the same controls and changer as my all-cherry wood deluxe three-channel RCA. I'm guessing the one in the photo is single ended?

Bill

[electra225]

What caused the output transformer to smoke?

[Motorola minion]

When I went to look at this unit, it was playing fine on FM but a mild red plate spot on the one output tube. The player was in dire need of a cartridge, there was no testing that.

There was no back cover so I could clearly see what I was getting; it was not recapped and I can only guess how often and long it was operated with a tube partly melting down..

[Motorola minion]

I was able to get the exact RCA original part! Moyers Electronics to the rescue again. I highly recommend contacting them if you need a n y t h i n g like this OEM part.

The installation was so easy, it looks almost original except the date code on this replacement transformer was late 60s!

Once I try the amp out in the cabinet, I will need to deal with bass feedback that affects the record player. This cabinet is not heavy, no back cover and no isolation of the speakers from the changer. The area between the tuner and changer is not supported from bottom of cabinet, so that's where it will go. The amp is rated 16 watts/channel from pp 6BQ5 with 12" woofers makes a lot of sound and vibration which limits volume and ruins our fun.

One method I used was to glue/screw an interior partition of 1/2 inch MDF between the speakers and central cabinet where the player sits. This was on a 64 Admiral with same issue. It sounded even better, pushing the bass out instead of redistributing and absorbing it within the cabinet. Mass=Bass

[Motorola minion]

Not much action in the RCA forum so I will update this thread lest it become moldy.

The TPM-12 had been up at the flea booth of an associate collector but unfortunately, the one output transformer got toasty. After I got lucky on an OEM replacement, the amp worked so well that the RP-215 player seemed to pick up too much bass, that is really not good if demonstrating to a buyer. Its your wife, not the feedback that should tell you to turn it down.

My plan is to reinforce the phono deck which likely requires a solid brace to a redundant solid bottom, fashion some type of back cover, etc. I really do not like to service and test units at the Antique mall, it returns to the test "barn" for some shake down testing.

[Motorola minion]

What caused the output transformer to smoke?

I believe it was going bad with shorted turns from overheating due to being operated that way by the previous owner.

[electra225]

Thanks for the update, Dave. I had wondered what happened to this project. Reckon Moyer would have a PT for my RCA TV?

[Motorola minion]

Thanks for the update, Dave. I had wondered what happened to this project. Reckon Moyer would have a PT for my RCA TV?

KCS102/Sams 396 ? Yes, I bet they would have a power transformer for an RCA. But use the part number from schematic, numbers stamped on RCA parts are often "drawing" numbers, for internal reference BUT no bloody use to technicians!

[electra225]

Thanks, Dave. I'll see what they can do for me.

[johneda66]

This is mine. Dad refinished it.

[electra225]

Welcome to the forum! We hope you will jump right in and join us often. Tell us more about what your interests are. Enjoy the forum!

[William]

Welcome, Johneda66, it is great to have you here on our forum. Feel free to look around and share your projects with us, we always like to hear what others are doing.

Bill

[Brettzky99]

I own this one now. Sounds great

[Motorola minion]

Thats a great model, I already miss it! Im working on my third RCA 3 channel "living stereo" of this era and while the tuner has the AM/FM feature, I can actually try it out at my place. Yes indeed, there is a classic rock station on FM that simulcasts on an AM station. I suspect the AM station was previously a sportstalk broadcast station, so if they dont get a contract to b-cast sportstalk, they have to keep the station active until they do. Simulcasting is one way to do that.

I can tune in the same station AM on 1490 and FM on 92.5, to get an idea how a predecessor to stereo sounds. This is where the AM broadcast only the L-R signal and FM station broadcasts R-L, making it sound like stereo as the L's and R's cancel out from your listening position.

The VM -815 I traded it for the TPM 12 was basically a roster adjustment. Simple fact is I see many RCA and no VM available here, I wanted to diversify my collection. Not wanting to ignore a great manufacturer only because none pop up for sale here.

[William]

I want you Motorola on the left, Brett. I have always thought that model to be a nice-looking model and probably sounds great.

Bill