[PhilcoFordTesla]

       

Hi, I just received my eBay TPA-1 score. 

It seems to power the amp up, makes a nice click anyhow but the turntable spins free and I couldn't detect any motor sound- so wondering if the platter comes off from the top, or what? If someone else has one that could post a picture of your battery cover I would appreciate it, but seems to be a simple part to make picture is out of focus, need to clean it up and reshoot!

Battery terminals look fine [Image: https://antiqueradios.com/forums/images/..._smile.gif] 65+ years of dirt and grime but except for a couple minor corner scuffs should clean up nice!

Thx,

-Bob

[morzh]

It was 5 or 6 yeas ago so I don't remember.
Best access is from inside.
This thing is rare so the only two cases I know of are on ARF forum.
I doubt anyone here has it.

[PhilcoFordTesla]

the plastic cap just pulls off and the usual snap ring, but not sure why the motor isn't getting power or isn't turning if it is getting power, I cross posted as well but need to finish the wayward marantz 15 before I use the bench space to open it further. Also need to replicate the battery cover, shouldn't be real hard, maybe clear plexi :-)

[morzh]

Test the motor. DC resistance etc. If no power simply trace wires.

Its all very simple there.
Also check the potentiometer that regulates speed, maybe its bad.

[PhilcoFordTesla]

Thx, Sure all makes sense, probably a lot easier than the 46-1213 with the transformer out or the Marantz 14/15 with the blown outputs and driver resistors, that one made me start thinking of other big amps here like the marantz and pulled a gnarly Phase Linear 700 (345wpc) out of the closet and found some funny guys including Perry WOPLSniffer https://forums.phxaudiotape.com/ who did the updated driver boards for my Sansui 5000 about to be installed, hardcore amp builders there! Carvers too

If PG&E doesn't shut our electricity down soon due to high winds, we keep getting alerts, maybe maybe maybe, then time to work on the battery record player on the kitchen table until the wife gets home from a 4 day trip to Disneyland tomorrow.

[PhilcoFordTesla]

I just started making a battery cover for mine, it looks like they used some wood screws or something to hold the cover on thasty are stripped out or drilled out on one side- I think some kind of "T Nuts or something would go good there- also what's with the selenium rectifier, was it ok to keep using on the one you worked on or maybe a 1N00X?  Time to check the pot for my motor failure issue.

Thx,

-Bob

[morzh]

What rectifier? TPA1 is strictly battery portable unit.

[PhilcoFordTesla]

it's for spike suppression, in series with a 10 ohm resistor across the motor, found the schematic of the whole unit, probably more effective with a silicon diode or even a germanium maybe with lower forward voltage drop- not sure what Vf is with a selenium?

[morzh]

It's been long time since I looked in the sch.
If this is how it's conencted then yes, probably for start/stop spike suppression.
Vf of selenium rectifier is about 1V/section so if you have say 4-section one you will see about 4V drop.

[PhilcoFordTesla]

This one has worse problems, I can see variable voltage on the motor leads but no turnny :-(  If I take the motor apart not sure where that will get me without trying, and then I'll want to pull the amp out and make it a display model- I mainly wanted the amp anyhow but it would have been nice to see it work.  Dad gave me an amp like this back in '56 with some other stuff to make some sort of an experimenter kit when I was 6.  I wasn't nice to it :-(  I loved the potted transformers and those little plug in transistors!

[PhilcoFordTesla]

On second thought it might make a cool .mp3 player with a hidden input jack somewhere underneath maybe on the battery cover I am making for it, would be a shame to permanently dismember it! However it looks pretty cool apart on the bench, if I leave the screws out I can just take a peak at that cool amp once in a while! All my stuff usually seemed to work better while they were/it was still apart! lol

[PhilcoFordTesla]

screw the input jack just did what I should have done for some of the old Philco's around here and try out some of these cheap little BT modules on ebay search dedicated bluetooth receiver and some neat mini to full function add in boards some with wide voltage input range. Thinking of patching in a couple of my favorite Li-Ion 18650 'tesla' batteries in a separate holder with a mini usb jack for recharge but not sure 3.3 V cells wold stress the transistors? After all D cells run like 1.57, new electrolytic for sure . . .

[morzh]

I'd say you are better off selling this TPA-1 to someone who will appreciate it as a time piece and get an amp separately. The amp inside in fact pretty crappy and so is the way it is assembled: 1-layer brown phenolic pcb board that has the traces separating under the transistors' weight.
It's value is not in being able to play MP3 which it will do but not in a good way. It's value is strictly historic.
It is your piece and you could do whatever with it but it's not many of these left so altering it won't add any value and won't make it a good playing piece unless you toss all the innards and replace it with a good amp and a good speaker.

[PhilcoFordTesla]

thx let me know if you just happen to find an amp in decent condition or notes from someone who has successfully repaired a motor from one, or even a whole parts unit!  As a museum piece its fine, need to try to clean the case up a bit and see how that goes . . . so far I guess we know of three of these on the net?

[PhilcoFordTesla]

suppose I do have other options after I do FA and succeed in repair or give upon the motor, might be some cylindrical low voltage motors that could be retrofitted, however I have been the subject of occasional incomplete project syndrome!