Yamaha A-1 refurb recap re-relay and repost (binding)

Hi brutal,

Do you have the part number for the THA Series panasonic filter caps used. Did the lugs or holes on the board need any mod or jiggling to get it all go in?

All the caps i looked at so far dont match the board holes so if the pana caps you installed were a perfect fit, I will get those if still available.

If not available any longer, if anyone reading this post knows of any good alternatives please let us know. I would like to keep the diameter stock at 50mm if possible.
 
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There's a few of those pesky VD1212's in there that got replaced with series 1N4148* ...

FG series on the VR/MC amp board...

Mostly KW on the power board...

Fusistors were replaced with metal film flameproof...

Hi,
this is my first e-m to this forum:D, I am warming up a little this thread:wave:
from some time I have Yamaha A-1, and this thread shows everything that I wanted to do with my A-1.
For this time I bypassed all of the el caps on dc board with Wima MKPs with excellent results.
Let me ask a few questions:
  1. 18000uF/63V Nichicons on main board looks very solid, they are noninductive type, is it realty worth to replace it with Panasonic 22000uF/80V? What other capacitor would you recommend for this replacement?
  2. What is benefit from replacing VD1212s with 1N4148 in series?
  3. Why did you get off original fusistors? Did they affect the sound?
Thank you in advance!
regards
Pilot1
 
Hi,
this is my first e-m to this forum:D, I am warming up a little this thread:wave:
from some time I have Yamaha A-1, and this thread shows everything that I wanted to do with my A-1.
For this time I bypassed all of the el caps on dc board with Wima MKPs with excellent results.
Let me ask a few questions:

18000uF/63V Nichicons on main board looks very solid, they are noninductive type, is it realty worth to replace it with Panasonic 22000uF/80V? What other capacitor would you recommend for this replacement?
Only you can tell if it is worth it. You'll not likely find the Panasonic caps in stock anywhere. Any quality cap you can find that approximates the values and, most importantly, fits the physical dimensions.
What is benefit from replacing VD1212s with 1N4148 in series?
VD1212 can go noisy. The series 1N4148 is the equivalent device (varistor). It's one of those components that most here repalce as a preventive measure. Along with any SC458 "outhouse" transistors you might find.
Why did you get off original fusistors? Did they affect the sound?
They tend to drift value over time and don't often do their job as protective devices.
Thank you in advance!
regards
Pilot1

Comments on the rebuild thread are welcome, but you may want to consider starting your own repair thread if you think your build is going to derail this thread.

Welcome to AK! It's customary to introduce yourself in a post and tell everyone a little about your interests.
 
Any need to change the rectifier diodes S5151(R) after 3 decades?
How about others, 1D431 and 1S1815, I couldn't find anything about them.
 
Out with the old.

Preemptively replaced the speaker relay as I usually have a few of these popular relays in the bin.
DSC_6338.JPG



I used a common Omron MY02-DC12 for the speaker relay (5A)
Avionic has found a higher rated Panasonic(10A?) lately but I can't find his post.


Hi guys, I have an a second A-1 i just got in that was not working and the usual cleaning of every switch in the unit has not resolved my scratchy left channel . From the Pre outs to another amp the everything is clear. So going over the schematics and board layout drawings I found that the relay you refer to as the speaker relay ( the clear one) is really for the Pre outs.
that relay is sealed unit and I can't see how the contacts would get dirty or oxidized. The Fijitsu RL- 6442-Hi32 I believe is the culprit. I posted in another thread about replacing the power switch. But thought I'd add this info here to make this a complete thread.

Switch used
http://www.digikey.com/product-search/en?mpart=P197EESB&v=141.

P197SBEE_sml.jpg


Now back to the relay. Here is the block diagram of the signal path.

24494147203_9136721722_o.png


Here are the designations for the wiring to the speakers and the Pre Outs.

25094851236_f76fce05ed_o.png


And here is the PCB layout( Easier to read than the schematic as the schematic does not show the relays path as clearly. I'm usually great at reading schematics but that section has me scratching my head.

24753507119_a2c7ff8184_o.png



If you follow SL( speaker left) and SR( speaker right) you will see they go to RY101 this is the fujitsu relay. Where as PR( Pre amp Right) and PL ( Pre amp Left) go to RY102 the sealed relay that you replaced.

So is there any replacement for this relay? Does anyone have a data sheet for it? I sent fijitsu a question about it for a cross reference or a data sheet. Lets see if they replay.


I may try to jumper the left channel to see if the distortion goes away.

Athanasios
 
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I wish I could edit my last post. I just realized both Relays work in conjunction with each other. So the sealed relay does work the speakers in and out. My Bad :(

Athanasios
 
Here's my Bourns Trimmer parts list, those used in the A-1 bolded:

Mfr PN MFR VALUE Watts Temp Range Dim Product
3299P-1-101LF Bourns 100 Horiz - side Trimmer, multiturn (pair on Amp Drive card)
3299P-1-201LF Bourns 200 Horiz - side Trimmer, multiturn
3299P-1-102LF Bourns 1k Horiz - side Trimmer, multiturn

3299P-1-202LF Bourns 2k Horiz - side Trimmer, multiturn (single 2.2K on PS card)
3299P-1-502LF Bourns 5k Horiz - side Trimmer, multiturn
3299Y-1-101LF Bourns 100 Vertical Trimmer, multiturn (pair on Pre-amp board)
3299Y-1-201LF Bourns 200 Vertical Trimmer, multiturn (pair 220 on Tone board) (pair 220 Ohm [VR301/VR302] on the VR/SW board for MC head amp distortion)*
3299Y-1-102LF Bourns 1K Vertical Trimmer, multiturn (pair on Electrolytic board)
3299Y-1-202LF Bourns 2k Vertical Trimmer, multiturn
3299Y-1-502LF Bourns 5k Vertical Trimmer, multiturn


This series of trimmer cases fit well on nearly every Yamaha I've redone. However, they do require the leads be bent to fit the PCB. I'll try to get a pic posted of the method I use.

Fusistors were replaced with metal film flameproof. Depending on voltage and current flow, 1/4W or 1/2W are preferred. However, all I had on hand were 1W so I'm risking some damage if there's a catastrophic failure. On the other hand, it's well known that transistors will always sacrifice themselves to protect their fusistors. :D My main goal was to provide stability and prevent drift that's common with the little buggers.

I used a common Omron MY02-DC12 for the speaker relay (5A)
Avionic has found a higher rated Panasonic(10A?) lately but I can't find his post.

*VR301 and VR302 (220 Ohm) are adjusted through a hole in this upside down board. If you replace them with 200 Ohm vertical pots, you will have to mount them on the back side (trace side) of the board and perform an adjustment that requires a distortion meter.

Where are the Trim pots I highlighted in Red located?

Also in the SM VR 301-303 are listed as 10k trim pots but your lis has them as 200ohms?

Just ordered the ones you had in BOLD and the panasonic relays.

Also there is a relay on the Pre amp board. Is there a part for this or is this a serviceable part. I think there is also a similar one on the Cap Board.

Athanasios
 
Where are the Trim pots I highlighted in Red located?

They're not, read my post - "Here's my Bourns Trimmer parts list, those used in the A-1 bolded:"

Also in the SM VR 301-303 are listed as 10k trim pots but your lis has them as 200ohms?

Just ordered the ones you had in BOLD and the panasonic relays.

Also there is a relay on the Pre amp board. Is there a part for this or is this a serviceable part. I think there is also a similar one on the Cap Board.

Athanasios

I just looked at the schematic again and VR301/302 are shown as 220Ohm. Best check again.

upload_2016-3-23_1-1-43.png
 
They're not, read my post - "Here's my Bourns Trimmer parts list, those used in the A-1 bolded:"

Ahh, I missed the word BOLDED ;)

I just looked at the schematic again and VR301/302 are shown as 220Ohm. Best check again.

View attachment 707806


I looked at the parts list in the SM

25891632372_22d2310bb3_b.jpg


I see this is why sometimes verification over trust is important as Ronald Reagan use to say ;)

Athanasios
 
Hi all, I jump into this post since I have (I believe) problems with the speaker relay in my Yamaha A-1. One channel is missing when powering on, and it only comes back by cranking up the volume or by manipulating the SPEAKER button several times.

I had this already last summer, but then the problem solved itself without any intervention on the machine. Now the problem came back about two weeks ago, and the effects are more pronounced than before.

So I would like to check the relay that is responsible for this. Is it the one in my picture below?

_dsc247610p2n.jpg
 
yep thats the one. Also check the two silver heat sinks on the PS board and make sure they do not move or are loose from the transistors.

If they are i would remove the heat sink, clean it and add more thermal grease then re install. If those transistors get hot they do not supply the right voltage to the relay which can cause it not
to have the right amount of pulling power on the coil to keep a constant contact. Just found this out my self , its in another thread .

Nashou
 
Thank you Nashou66. So, I desoldered the relay during my lunch break and started cleaning it. I had to go back to work, so I didn't solder it back in yet. And I will check the heat sinks. I had a similar problem with my T-7… some transistors (with heatsink) came loose since the solder dried out.
 
So, I managed to clean the relay with a piece of thick paper, soaked with contact cleaner. And without breaking anything. The most difficult part was getting the transparent cap off the relay. I also checked those transistors with the heatsinks, and in fact, the screws were slightly loose, so I just tightened them carefully.

And it seems to have worked out, both channels are alive immediately after the relay closes. I tested it 3-4 times. I will report back after a while.
 
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So, I managed to clean the relay with a piece of thick paper, soaked with contact cleaner. And without braking anything. The most difficult part was getting the transparent cap off the relay. I also checked those transistors with the heatsinks, and in fact, the screws were slightly loose, so I just tightened them carefully.

And it seems to have worked out, both channels are alive immediately after the relay closes. I tested it 3-4 times. I will report back after a while.

Good Work !!!

Nashou
 
Thanks for the good info to help me refurb my old A-1. Did you ever work up a master list of recommended replacement parts?

Out with the old.

There's a few of those pesky VD1212's in there that got replaced with series 1N4148* along with any fusistors and all the trimpots were replaced with Bourns multiturn units.
DSC_6347.JPG


FG series on the VR/MC amp board. All boards cleaned and defluxed after the rework.
DSC_6333.JPG


Mostly KW on the power board, yea overkill, but cheap enough for me when ordered in bulk from Mouser.
I may just start using KT (105* audio caps) for power if I can find all the right values.
DSC_6334.JPG


Raised the power trans heatsinks off board with a couple shoulder washers. There's a .47uf polar lytic still hiding in there still to be dealt with. I didn't clean the dust off well enough when I was gathering info to see it was not simply the same as the other one nearby.
DSC_6344.JPG


The A-1 already has polypropylene film bypass caps installed with the filter caps. Panasonic T-HA series and a couple ES Muse bipolars here. Preemptively replaced the speaker relay as I usually have a few of these popular relays in the bin.
DSC_6338.JPG


Vampire BPHEX goodness.
DSC_6346.JPG


Stock screw insert block removed intact and replaced with a solid delrin backing plate to mount the new posts.
A near perfect fit. No trimming required.
DSC_6345.JPG


Heatsinks get washed and new mica/thermal paste used just like Yamaha intended.
DSC_6392.JPG


Those OE Sankens are heavy duty puppies.
DSC_6398.JPG


No lytics whatsoever on the amp board.
DSC_6404.JPG


I felt a bit let down by all the A-1 hype when I first got it. I thought it was a little thin at first listen. It sounds fuller now than it did prior to the recap. Bass has more punch to it and the soundstage is slightly improved. I didn't get a chance to listen to any vinyl on it before, and don't own an MC cart, but surely the move from regular ol caps to FG series Nichicons should improve things. If nothing else, I know it's good for another 30 years.

Now if I could just get the idle current to adjust... :scratch2:
The SM wants a 8* 70W load connected to the speaker outputs during adjustment and I don't have anything built yet. Seems bench speakers aren't cutting it.

* I wasn't paying attention to the board markings and mis-oriented one of the 4148 series pairs used to replace the VD1212 regulator diodes. That little mistake caused a fair bit more work, one 2SA914 transistor and a grip of resistors.

Edit 12-18-2011 -- I seem to get a lot of PM's asking for parts lists.

As can be found readily on AK, VD1212 diodes are replaced with two 1N4148 or similar switching diodes wired in series.

Here's my Bourns Trimmer parts list, those used in the A-1 bolded:

Mfr PN MFR VALUE Watts Temp Range Dim Product
3299P-1-101LF Bourns 100 Horiz - side Trimmer, multiturn (pair on Amp Drive card)
3299P-1-201LF Bourns 200 Horiz - side Trimmer, multiturn
3299P-1-102LF Bourns 1k Horiz - side Trimmer, multiturn
3299P-1-202LF Bourns 2k Horiz - side Trimmer, multiturn (single 2.2K on PS card)
3299P-1-502LF Bourns 5k Horiz - side Trimmer, multiturn
3299Y-1-101LF Bourns 100 Vertical Trimmer, multiturn (pair on Pre-amp board)
3299Y-1-201LF Bourns 200 Vertical Trimmer, multiturn (pair 220 on Tone board) (pair 220 Ohm [VR301/VR302] on the VR/SW board for MC head amp distortion)*
3299Y-1-102LF Bourns 1K Vertical Trimmer, multiturn (pair on Electrolytic board)
3299Y-1-202LF Bourns 2k Vertical Trimmer, multiturn
3299Y-1-502LF Bourns 5k Vertical Trimmer, multiturn

This series of trimmer cases fit well on nearly every Yamaha I've redone. However, they do require the leads be bent to fit the PCB. I'll try to get a pic posted of the method I use.

Fusistors were replaced with metal film flameproof. Depending on voltage and current flow, 1/4W or 1/2W are preferred. However, all I had on hand were 1W so I'm risking some damage if there's a catastrophic failure. On the other hand, it's well known that transistors will always sacrifice themselves to protect their fusistors. :D My main goal was to provide stability and prevent drift that's common with the little buggers.

I used a common Omron MY02-DC12 for the speaker relay (5A)
Avionic has found a higher rated Panasonic(10A?) lately but I can't find his post.

*VR301 and VR302 (220 Ohm) are adjusted through a hole in this upside down board. If you replace them with 200 Ohm vertical pots, you will have to mount them on the back side (trace side) of the board and perform an adjustment that requires a distortion meter.
 
I'm working on my A-1 bit by bit. When ordering trim pots, does lead free (LF) make a difference? Just curious in general for these vintage components that were not lead free.
 
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