Vintage SONY TA-F55

[d052057]

Any one by chance knows the light bulb spec for Sony TA-F55?
The light bulb is to display volume control for the unit.

Thanks.

 

[Old Guy8]

I have one, since 70's. Not a technician. Second time lights quit, I found schematic, but no lamp specs. Volume lamps are four in series in 45 volt circuit. I replaced two bad with 5 volt lamps. Did not have any luck repairing mine. Possibly a power supply problem. None of my lamps work. All other funcions fine. I gave up. Good luck.
BTW, welcome to AK.

 

[d052057]

I have one, since 70's. Not a technician. Second time lights quit, I found schematic, but no lamp specs. Volume lamps are four in series in 45 volt circuit. I replaced two bad with 5 volt lamps. Did not have any luck repairing mine. Possibly a power supply problem. None of my lamps work. All other funcions fine. I gave up. Good luck.
BTW, welcome to AK.

Mine says 42.5v. You should put 4 10 or12v light bulbs in series the they should work.

 

[Old Guy8]

Mine says 42.5v. You should put 4 10 or12v light bulbs in series the they should work.

I was quoting from memory. May have been 12 v lamps. May revisit again, to see if I can get them. working.

 

[d052057]

I was quoting from memory. May have been 12 v lamps. May revisit again, to see if I can get them. working.

The 12v lamps work.

 

[Old Guy8]

Will check what I used. thanks. Still don't know why ALL the lamps are out. Not just the series volume lamps. Will look into.

 

[d052057]

Do u know the voltage of the other bulbs?

 

[Old Guy8]

I'll look over the repair manual/schematic again. The pages I printed only have Sony part numbers for the lamps. No specs on lamps. Believe I found schematic at hifiengine site.

 

[Old Guy8]

Have you looked for that service manual/schematic on hifiengine site? I do not remember any bulb specs listed though.

 

[d052057]

i don't have it. I suspected that it is 12v bulb. It is 2mm grain light bulb and I do have 4.7mm instead. It won't fit.

 

[dlalkovic]

Instead bulbs I used LED with minor intervention in electronics wich drives bulbs. There is two current sources: one for volume indicator and one for other indicators. You just need to change two resistors in each cs in order to define different size of current (about 10 mA). 330 ohm resistor instead 110 ohm between B+ and emitter of PNP transistors in cs. Now connect LEDs in series (4 white high briight for volume and 9 yellow and green for other indicaticators). Tricky part is connect diodes in exact position-anode from one to catode of another. Of course you need a service manual.
My first post on AK

 

[dlalkovic]

LEDs are 3 mm.

 

[Old Guy8]

Instead bulbs I used LED with minor intervention in electronics wich drives bulbs. There is two current sources: one for volume indicator and one for other indicators. You just need to change two resistors in each cs in order to define different size of current (about 10 mA). 330 ohm resistor instead 110 ohm between B+ and emitter of PNP transistors in cs. Now connect LEDs in series (4 white high briight for volume and 9 yellow and green for other indicaticators). Tricky part is connect diodes in exact position-anode from one to catode of another. Of course you need a service manual.
My first post on AK

Welcome to AK,
This is an old thread you posted to. Date is in lower corner. I was not original poster. I ended up giving my Sony to a local shop. Let them fix it and sell if economical to them. I had since new.
It was a versatile amp for MM or MC carts. Never tried MC with it. Lamps only reliability issue I had.
LED's is the best solution, IMO, so solve issue.