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Yamaha A-1 amplifier thump on power off.

That relay is almost mandatory change. It can cause complete drop out or weird noises from the speakers even when nothing is connected to the amp.
Been there done that.

Athanasios
 
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Ha ha, no, I’m not that brave.
Your original post also mentioned “Double check the op voltage and pin-out...” which led me to think that there might be alternatives.
Actually, how do I check the operating voltage on my machine? It’s a UK one so it takes a 240V mains voltage. Would this have any effect on this choice of relay?
 
Hifibythekg said:
Actually, how do I check the operating voltage on my machine?
Click to expand...
Probably meant the relay operating voltage, typically 12VDC or 24VDC hence MY2-02-DC12 and ...-DC24 part numbers. Check the power rail in the service manual or carefully measure voltage across the relay coil (near diode?)
 
Thanks @mbz
My board says NAO7130 (also the code LC68980) and so it’s a US model as per attached photo?
Is this sufficient to confirm that it’s 12V?
From the SM I’m unable to check the power rail I’m afraid.
 
Photo of my board is from prior to restoration.
Do these shed any further light? Obviously the SM scans are just the usual ones downloaded from the internet and not one that came with this secondhand amp.
CBB409F1-A8A3-4E45-BDDB-1EF1D1FB4F02.png649DAAAE-C9BF-448A-AE20-B14790944DA0.pngEB5B13F1-F939-498A-A32C-C87F20C6D11D.pngCFFBA153-8BAD-4922-ACB1-A08B09C8EB52.png
 
Sorry about that, had something of a "Blonde moment". The relay (RY101) in the A-1 is is a 12V item, this is independent of the mains AC.

It's not a bad amp, I play mine a fair bit, quite enjoyable...
 
Haha, no worries.
Yes, I’m really enjoying mine. Just got hold of a Canton Plus-S and Plus-C subwoofer (never thought that I’d use such a thing) but it’s a marvellous sound.
Would be good to hear from others what the particular sonic qualities/strengths/weaknesses of this amp are given its unusual circuitry.
 
RY101 is the speaker relay. Thats the one you want to change out that causes issues. RY102 aI don't think causes problems much. Best to ask @avionic
about that one. But I never changed that one out.

EDIT: Changed the relay designations thanks to avionic for pointing it out in a couple post below.

Athanasios
 
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O my!
I think I have some replacement reeds for RY102.
(Thought it was strange that after cleaning the contacts it still played up, although perhaps it’s the coil or something else failing.)
Otherwise could you please tell me the replacement relay you’ve used for RY102?
 
Hifibythekg said:
O my!
I think I have some replacement reeds for RY102.
(Thought it was strange that after cleaning the contacts it still played up, although perhaps it’s the coil or something else failing.)
Otherwise could you please tell me the replacement relay you’ve used for RY102?
Click to expand...

Id have to try to find my thread, I didn't keep notes on it.

Let me see if I can find if its in that thread.

Athansios
 
Hifibythekg said:
O my!
I think I have some replacement reeds for RY102.
(Thought it was strange that after cleaning the contacts it still played up, although perhaps it’s the coil or something else failing.)
Otherwise could you please tell me the replacement relay you’ve used for RY102?
Click to expand...
It is highly recommended you replace rather than repair old relays. In some circumstances that involve unobtanium parts, one could argue for repair
 
So given these random cut outs, which relay replacement should I prioritise?
And can anyone recommend a replacement part for RY102 reed relay?
Thanks everyone
 
avionic said:
RY101 is the speaker protect relay (MY2 ) ... RY102 is a reed relay

View attachment 2686018
Click to expand...


Yes, I got the designation wrong, I'll change my post. I changed out the clear plastic one. Not the metal can type.

51818237782_f0facb01bf_b.jpg


Athanasios
 
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