Rca ColorTrak Spacesaver turns on and off repeatedly

[TvGuru87]

Hello all, i recently got an Rca ColorTrak Spacesaver E09525KW with the Tx81c chassis off ebay. When i unpacked it and turned it on it worked fine. Now when i plug it in it automatically turns on and off continuously by itself and will only stop if you unplug it. Does anyone know what could be the problem?

[zeno]

OK remember them well. I dont have a manual but first I would
check for a cracked PCB from shipping. The other thing was a transistor
in the power supply went left & right. That was updated & had a new
part ## if you look for one.
One thing on this set. The main filter can stays charged & I would get
bit on almost every one. You should discharge it especially when
soldering or you may put 150 volts in the wrong place.
IIRC Johnct was RCA & can help you more.

73 Zeno
LFOD !

[JohnCT]

Originally Posted by zeno

Johnct was RCA & can help you more.

73 Zeno
LFOD !

You pretty much covered it a lot better than I would have and brought back memories! I had totally forgotten about that transistor. I do remember a standard SK or ECG type sub would run hot (hotter than the original as that ran hot). Was there a capacitor that caused that transistor to run hotter than it did ordinarily???

I've got a ton of TX notes at my shop. I'll check tomorrow and paste what I have.

John

EDIT: found some notes on my old laptop (surprised it boots).

TX81 cycling: CP01 (100uf/35v) *very common*
Tp15 P/N RCA #198752 (the transistor that Zeno mentioned)
DP18 (use ECG580)

Dead or otherwise with intermittent issues:

Cp32 --202044
Tp10--198794
Rp41--198678
Cp06--198559
Cp08--190501
Tp06--198748
Fp01--198605.

There is more... these were very common and were made by the millions, which is why there is so many notes. Generally, the first three tips are the most common IIRC.

[TvGuru87]

Originally Posted by JohnCT

You pretty much covered it a lot better than I would have and brought back memories! I had totally forgotten about that transistor. I do remember a standard SK or ECG type sub would run hot (hotter than the original as that ran hot). Was there a capacitor that caused that transistor to run hotter than it did ordinarily???

I've got a ton of TX notes at my shop. I'll check tomorrow and paste what I have.

John

EDIT: found some notes on my old laptop (surprised it boots).

TX81 cycling: CP01 (100uf/35v) *very common*
Tp15 P/N RCA #198752 (the transistor that Zeno mentioned)
DP18 (use ECG580)

Dead or otherwise with intermittent issues:

Cp32 --202044
Tp10--198794
Rp41--198678
Cp06--198559
Cp08--190501
Tp06--198748
Fp01--198605.

There is more... these were very common and were made by the millions, which is why there is so many notes. Generally, the first three tips are the most common IIRC.

I checked CP01 and it reads right on the money but i replaced it anyways, and it still has the same problem. I can’t seem to find TP15 or DP18 on the circuit board unfortunately though.

[JohnCT]

Originally Posted by TvGuru87

I checked CP01 and it reads right on the money but i replaced it anyways, and it still has the same problem. I can’t seem to find TP15 or DP18 on the circuit board unfortunately though.

There were several versions of the TX81. It's possible the C version doesn't have the TP15, or it may have been redesignated. Unfortunately, I tossed all my RCA paper manuals years ago. If it was ever on DVD ROM, I'll still have it. I'll check later today.

As Zeno mentioned, solder issues are a problem in the TX series. Look at the pins around the fly (pin 10 especially) and the board in general. I'll check the rest of my notes at work later today.

John

[zeno]

IIRC TP15 is front & center on the PCB. Look at the bottom of the
chassis for a darkened spot from the xistor overheating. Its
a small xistor.
The part # listed for TP15 may be the old or new number. IIRC there
is still an old RCA parts distributor with NOS parts. They should have
a bin full of them. Sry I dont remember there name.

good luck es 73 Zeno
LFOD !

[TvGuru87]

Originally Posted by zeno

IIRC TP15 is front & center on the PCB. Look at the bottom of the
chassis for a darkened spot from the xistor overheating. Its
a small xistor.
The part # listed for TP15 may be the old or new number. IIRC there
is still an old RCA parts distributor with NOS parts. They should have
a bin full of them. Sry I dont remember there name.

good luck es 73 Zeno
LFOD !

I’m not seeing a TP15, nor am i seeing any burnt spots on the board. I’m also not seeing any cracks on the board either.

[zeno]

These sets had a screwy way of labeling parts. Ex. TP15 means
" Transistor Power supply #15" Every stage has a designation.
Most sets used numbers like Q801. The 800 series numbers were power supply.
IIRC TP15 was the on/off for the set. Hows about a pix of the chassis ?
Also if you have a schematic post that.

73 Zeno
LFOD !