I need help on switching on my Vintage SONY TA-F5A

subbanna

subbanna
Hi Guys,

I just received a Vintage Sony TA f5a from a friend of mine. It was working fine before it was shipped. Once landed, it is not firing & there are no meter lights or any activity.

I checked the fuse & they seem to be ok and show continuity. This amp is in pristine condition and i really want to see it back to life.

I hope it is a small issue. It is a 220/110v unit and I had made sure it stays on 220v before switching it on.

Please help me to bring it back to life.

Regards
https://www.flickr.com/photos/prakash_subbanna/
 

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Hi Guys, I need some experts to solve some issues regarding my Vintage integrated amp. SONY TA- F5A.

The Amp works for about 30 mins. to 1 hour of play time. Switched on again the set of resistors in the power supply unit blows off.

The resistors are R601, R602, R603 rated at 100 ohm/ 1 watt each. I got it replace once but, it blew off again the moment the power switch is depressed. There are two fuses in the circuit, 5 amp & 2.5 amp both intact after the blow-off of resistors.

I wonder what else might be wrong in this part of the circuit. I am attaching the image of this circuit diagram for further analysis.

Thanks & Regards.

https://www.flickr.com/photos/prakash_subbanna/
 

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A magnified image of the circuit diagram is attached for convenience.

Regards.
 

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Hi, I can´t help you, but I´m sure others can.

Your question is posted in the wrong area though. Ask a moderator to move this thread to DIY. I´m sure you will get help there.
 
Nice unit there, sub!

I have its little brother F4A & its such a sweet player. Yea, someone should be able to help you as Judas stated when it gets to the appropriate forum. Lots of technical knowledge here to help.

Rome
 
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@kcvet, On arrival there is no visible damage. It just did not switch on...The sender has a picture of its working and meter lights on just before packing it.

@Rome, Nice to know you have his little brother the F4A.
 
R601, R602, R603 are soft start resistors .
what should happen at power on is the power should go through them resistors very briefly then the power relay should kick in and bypass them .
what appears to be happening is the power is going through the resistors instead of the relay thus burning them up .
ok first thing to check/test is r275 10 ohms it appears to be a thermal fuse of sorts . and r336 1.1 k ohms .
read section 1 outline in the manual it explains things a little .
 
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@kcvet, On arrival there is no visible damage. It just did not switch on...The sender has a picture of its working and meter lights on just before packing it.

@Rome, Nice to know you have his little brother the F4A.

examination time. drop the bottom cover off. and use a magnifying lense to examine the PCB for cracks. some are not visable to the naked eye

ozplh.jpg


the large box on the left is the PPS.

zksap0.jpg


a good place to start. if your a DIY guy use a VOM/DVM check for AC in to the supply. AC in there?? check for DC out. AC in no DC out problem is here. No AC in trouble shoot why. a print would be invaluable here
 
service manual: http://www.hifiengine.com/manual_library/sony/ta-f5a.shtml


It probably took a near straight drop if no physical damage. that main board with the caps could deflect quite a bit if there is no center support. Also check the pcb ground screws and other chassis screws. Check the traces on that p.s. board.

I had a large main board on a sony deflect about a 1/2in and it hit the chassis at one point and drove the pig tails of a 30v cap out. Somebody didn't trim the legs off very close so it was easy to calculate the deflection.
 
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service manual: http://www.hifiengine.com/manual_library/sony/ta-f5a.shtml


It probably took a near straight drop if no physical damage. that main board with the caps could deflect quite a bit if there is no center support. Also check the pcb ground screws and other chassis screws. Check the traces on that p.s. board.

I had a large main board on a sony deflect about a 1/2in and it hit the chassis at one point and drove the pig tails of a 30v cap out. Somebody didn't trim the legs off very close so it was easy to calculate the deflection.

thanks for the link. I joined and downloaded his model which can also be printed
 
kcvet.. it's a good site but I don't download as many as I used to I just open them up.

Interesting power supply layout. I guess we have to wait for the OP for some feedback.
 
kcvet.. it's a good site but I don't download as many as I used to I just open them up.

Interesting power supply layout. I guess we have to wait for the OP for some feedback.

it is a good site. I have an ole Teac A-6010 reel to reel that was on there. so I have most of the IM downloaded. there's no mechanical diagrams or parts list. but i know a fee based site that sells the original complete service manuals.

thats a PPS he has. a Pulse Power Supply
 
Guys, really some interesting observations and analysis of the problem. The update is the Soft resistors R601,602,603 was replace once again just to check again...
The amp worked for about an hour. Resistors was hot for just a moment and then settled down to normal temp. The Amp is sounding very good. It was switched off.

The next time when it was switched on after a few hours, immediately a shorting noise was heard from the same resistor bank and could see a visible puncture hole on 602.
Resulting in no panel light or any life what so ever.

As suggested the switching relay may be the culprit b'cos the amp was sitting unused for a very long time i suppose.

There is no visible PCB cracks or shorts observed. So shipment damage can be ruled out.

My friend who has all the necessary equipment is trying to corner the problem.

The suggestions from the esteemed members are very helpful. I am sure we should be able to sort it out.

Btw. its a 220/110v model and set to 220v. Manual downloaded for reference.

Will keep updating as when there is a progress on this restoration. I really appreciate your time and effort.
Thanks & regards.

https://www.flickr.com/photos/prakash_subbanna/
 
Hi Guys, An update on breathing life into SONY TA-F5A, Well all the possible problems discussed were checked.

A friend of mine who is equipped and understands DIY is handling the Amp. All member suggestions are passed on and taken in to process of problem solving.

There is no visible damage on the pcb, all the caps seem to be fine physically and working.

When the resistors R601-603 are replaced the Voltages are checked at required points and meeting the values.

The Amp played at its Sonic best for few hours and was switched off. After cooling off period of 36 hours i switched it on...There is no life...( no meter lights or any sound of relays switching.)... Amp Dead.!

One observation is ...The bank of 3 resistors R 601 - 603 get warm initially for a few seconds every time and then settles to cool.

One conjuncture is...As the Amp was sitting idle for a long time.. we think Relay RY601 might be the culprit. We wish to change it to see if it makes any difference.

Guys, what is the value of RY601 (RELAY). The white color cube which sits on the board. next to resistors. I am not able to get it from the manual.

But, as long as the Amp plays it sounds very very nice.

Thanks & Regards.
 
Usually 24vdc rated, some less. Just put your DMM leads on the power leads to the relay circuit?.. you'll get the voltage. Check the circuits to the relays, too. while you're in there. Gently tap on the relay to see if engages.
 
Hi Guys,

An update and Good news. SONY TA-F5A seems working. Let me tell you the sequence of events.

The bank of resistors R601-603, kept on blowing as when replaced.

As suggested by @Binkman, I did check the SURGE CURRENT RELAY RY 601 it was not switching on..

Replace the RY 601 RELAY 24v & The bank of resistors 601- 603.

Now i hear a distinct ' Click " when the power switch is depressed. It take a Second to power on...!!

I presume that RY601 was the culprit by not switching on ( rather shorting ) the Resistor bank. Which in turn kept on heating the resistors until it blew off and stopped working.

I hope this is solution & no more nasty surprises for this sweet sounding Vintage amp.

Thank you all for your support and guidance. This forum rocks.

I shall keep posting the long time run-in results.

Thanks again & regards from Bangalore, India.
 

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