Poineer A-209R

Karl vd Berg

Member
2012-07-16 12:49 am
Houston, we've got a problem.

(Hi all!) :rolleyes:

Poineer A-209R (Direct Energy MOS)

I've got this amp for a few coins today... because it's dead.

No sign of life. Well, just checked external fuses, etc, and they're ok.

The Trafo's secondary doesn't supply anything. It's supposed to provide 14, 16, 18 VAC (Brown, Black and Gray, respct.)

Already measured for continuity across all the points. Everything "beeps" regurlarly.

[IMGHTTPDEAD]http://img833.imageshack.us/img833/285/p5270742.jpg[/IMGHTTPDEAD]

[IMGHTTPDEAD]http://img59.imageshack.us/img59/8049/p5270741.jpg[/IMGHTTPDEAD]

[IMGHTTPDEAD]http://img266.imageshack.us/img266/6779/p5270743.jpg[/IMGHTTPDEAD]

[IMGHTTPDEAD]http://img96.imageshack.us/img96/1380/supplyu.jpg[/IMGHTTPDEAD]

Any idea?
 
Houston, we've got a problem.

(Hi all!) :rolleyes:

Poineer A-209R (Direct Energy MOS)

I've got this amp for a few coins today... because it's dead.

No sign of life. Well, just checked external fuses, etc, and they're ok.

The Trafo's secondary doesn't supply anything. It's supposed to provide 14, 16, 18 VAC (Brown, Black and Gray, respct.)

Already measured for continuity across all the points. Everything "beeps" regurlarly.

[IMGDEAD]http://img833.imageshack.us/img833/285/p5270742.jpg[/IMGDEAD]

[IMGDEAD]http://img59.imageshack.us/img59/8049/p5270741.jpg[/IMGDEAD]

[IMGDEAD]http://img266.imageshack.us/img266/6779/p5270743.jpg[/IMGDEAD]

[IMGDEAD]http://img96.imageshack.us/img96/1380/supplyu.jpg[/IMGDEAD]

Any idea?

Can you measure primary AC voltage? Secondary AC voltage? Can you check rectifier? Could be power cord problem too.
 
Last edited:

Karl vd Berg

Member
2012-07-16 12:49 am
Indeed could be the thermal fuse. There's 230V across the points, but no continuity across them.

I have no idea how to open the transformer to see/look for this thermal fuse... :confused:

How does it look like? And what's the function of it? Sometimes we have AC reaching 250V...
 

Mooly

Administrator
Paid Member
2007-09-15 8:14 am
It will be buried in the windings (usually non replaceable). You should get a low ohms continuity between L and N terminals. You might "see" the fuse or deduce its location from any extra wires going into the transformer from the existing pins.

If its failed it could be anything from no fault other than the fuse to a short (such as a rectifier or outputs)
 

Mooly

Administrator
Paid Member
2007-09-15 8:14 am
This looks like the fuse. It should read zero ohms between these points
 

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Karl vd Berg

Member
2012-07-16 12:49 am
It will be buried in the windings (usually non replaceable). You should get a low ohms continuity between L and N terminals. You might "see" the fuse or deduce its location from any extra wires going into the transformer from the existing pins.

If its failed it could be anything from no fault other than the fuse to a short (such as a rectifier or outputs)
I only hope I don't have to replace thr trafo, bacause it's suppose to cost something around 120 euros!! I had the same thing while ago with a Rotel amp reported here. But that was easy to replace with a common black and two 18VAC red wires from secondary.

Here instead we have three different outputs 14, 16 and 18 from the brown, black and grey's secondary...

Pictures below showing primary and secondary and from top:

[IMGDEAD]http://imageshack.us/a/img845/9277/p5270747.jpg[/IMGDEAD]

[IMGDEAD]http://imageshack.us/a/img515/860/p5270748.jpg[/IMGDEAD]

[IMGDEAD]http://imageshack.us/a/img59/8338/p5270749.jpg[/IMGDEAD]

[IMGDEAD]http://imageshack.us/a/img7/6189/p5270750.jpg[/IMGDEAD]

[IMGDEAD]http://imageshack.us/a/img850/3880/p5270751.jpg[/IMGDEAD]

[IMGDEAD]http://imageshack.us/a/img13/2734/p5270752.jpg[/IMGDEAD]
 
There aren't 3 different outputs. It's just a centre tapped transformer the same as the Rotel was. While the service manual doesnt state the secondary voltages, from looking at the power supply capacitors and the voltage rails mentioned on the power amp side, it looks like 25-0-25VAC to me. It'd certainly get the amp working using those voltages.
 
My guess on why this has failed would be the same as that Rotel - your mains should be 230V but it is actually more like 250V. The extra power could well be responsible for making the transformer overheat and blow the thermal fuse. If you can get transformers rated for 240V primary, it may be better.

Also, commercial stuff tends to cut corners on this sort of thing. You may find a good quality toroid transformer will not have a problem compared to a cheaply made EI.
 

Karl vd Berg

Member
2012-07-16 12:49 am
My guess on why this has failed would be the same as that Rotel - your mains should be 230V but it is actually more like 250V. The extra power could well be responsible for making the transformer overheat and blow the thermal fuse. If you can get transformers rated for 240V primary, it may be better.
Yes, I guess it was the spikes of voltage at that time that blown the Rotel's trafo away. 230VAC seems to be stable since then.

Thought so. You could put a 100 watt bulb across those points and test the rest of the amp :)
I have to build my dim bulb tester yet :)

Any chance of fix this transformer or replacement is the only solution? :)
 

Karl vd Berg

Member
2012-07-16 12:49 am
Pioneer A-209R

The only direct fix for the transformer would be to bypass it's thermal fuse. I would not recommend this. If the transformer has gotten hot enough to blow the fuse, the primary winding could be damaged.
I just took the main PCB off to desolder the rectifier bridge and check if it's still OK, before take action with a new trafo.

[IMGDEAD]http://img59.imageshack.us/img59/8673/p5270753.jpg[/IMGDEAD]

[IMGDEAD]http://img843.imageshack.us/img843/8430/p5270757.jpg[/IMGDEAD]

iaxxaxxai said:
The large power supply filter caps look possibly bad as well. I can't say for certain from the photo, but they look like their cases have expanded. Usually a sign they should be replaced.
Here is a close-up of them :)

[IMGDEAD]http://img541.imageshack.us/img541/3038/p5270759.jpg[/IMGDEAD]