Sony PS-X70 issue - arm randomly automatically lifts

[cabkab]

I have a gorgeous Sony PS-X70 that I really love but it has a mysterious issue that I am wondering if anyone here might be able to help me pinpoint. There is an "up/down" button to raise or lower the tonearm. When you initially turn on the unit the "up/down" LED defaults to on and the arm always raises. I think this might be the normal behavior but I don't see it mentioned anywhere. The problem is that while playing music the light will sometimes do a little flicker and then eventually it will come on randomly and the arm will raise and remain raised until I push the button to lower it again. It's quite annoying to have the music randomly stop. I opened up the unit and I cleaned the up/down button with contact cleaner. It seems to still be happening. Does anyone have any suggestions or insight into what might be causing this?

 

[newzealand]

hi there
im in the process of repairing a ps-x700 that the arm will not lower
what i found was a IC that had failed ,an op amp to be precise , the IC is coupled to a few capacitors,
in my unit the caps are out of spec ,so i can only think that is a contributing factor in its failure,
im not sure about your model but it could very well be similar ,
doing a re cap may help? if its not totally failed the lowering system, it could be a cap and the IC may be still working?
but i have not finished the job yet and could be more problems to find,im awaiting parts,
ill keep you in the loop if you like?

https://audiokarma.org/forums/index.php?threads/sony-ps-x700-repair-thread.936414/

this is a thread regarding the repair ,ill do my best to help you if you want it,
mike

 

[cabkab]

Super cool, do you have to pull the whole mainboard to replace caps? How easy is it to get to the point of replacing the caps?

hi there
im in the process of repairing a ps-x700 that the arm will not lower
what i found was a IC that had failed ,an op amp to be precise , the IC is coupled to a few capacitors,
in my unit the caps are out of spec ,so i can only think that is a contributing factor in its failure,
im not sure about your model but it could very well be similar ,
doing a re cap may help? if its not totally failed the lowering system, it could be a cap and the IC may be still working?
but i have not finished the job yet and could be more problems to find,im awaiting parts,
ill keep you in the loop if you like?

https://audiokarma.org/forums/index.php?threads/sony-ps-x700-repair-thread.936414/

this is a thread regarding the repair ,ill do my best to help you if you want it,
mike

 

[newzealand]

Super cool, do you have to pull the whole mainboard to replace caps? How easy is it to get to the point of replacing the caps?

hi there
it has 3 pcb's in which i will need to remove ,power supply , main pcb , control pcb, it does look involved to remove the pcb's but it needs to happen ,
still waiting for the parts but when they arrive ill put some pics up,it might help you out if it is similar,

 

[cabkab]

hi there
it has 3 pcb's in which i will need to remove ,power supply , main pcb , control pcb, it does look involved to remove the pcb's but it needs to happen ,
still waiting for the parts but when they arrive ill put some pics up,it might help you out if it is similar,

Here is the gut shot of my unit. Im not sure how much Id have to disconnect to get this board up enough to have access to the underside. Anyone ever work on one of these?

 

[newzealand]

Here is the gut shot of my unit. Im not sure how much Id have to disconnect to get this board up enough to have access to the underside. Anyone ever work on one of these?
View attachment 2035664

it looks similar to the x700 but not the same,
it does look like some disassembly needs to take place but not to bad ,
im going to detach three sides of the pcb's and flip them over and recap the pcb's that way,
some parts for my recap are on back order ,this means a wait of about 7-10 days ,
if it helps ill make sure i take lots of pics of how i do it,
good luck
mike

 

[cabkab]

it looks similar to the x700 but not the same,
it does look like some disassembly needs to take place but not to bad ,
im going to detach three sides of the pcb's and flip them over and recap the pcb's that way,
some parts for my recap are on back order ,this means a wait of about 7-10 days ,
if it helps ill make sure i take lots of pics of how i do it,
good luck
mike

Very cool. Yeah, last time I had it open I wasn't thinking about pulling up the board so I didn't really pay attention to how the wires were run to see what might need to be disconnected or unsoldered to lift it up. I am super capable of replacing thru-hole components but I just hate too much disassembly and usually tap out when there is too much of a burden to getting to that point. I love when they make this stuff accessible without disassembly. I worked on a batch of vintage sony walkmans last year and I think I got my fill of taking apart electronic sandwiches back then. I never really did like puzzles! LOL Working on guitar amps is so much easier!

 

[newzealand]

Here is the gut shot of my unit. Im not sure how much Id have to disconnect to get this board up enough to have access to the underside. Anyone ever work on one of these?
View attachment 2035664

when you had it apart did you look for any discoloration on any of the ic's? did all the caps look good?

 

[newzealand]

Here is the gut shot of my unit. Im not sure how much Id have to disconnect to get this board up enough to have access to the underside. Anyone ever work on one of these?
View attachment 2035664

how is it in FL these days?i lived there for a year in 2000 ,fort lauderdale, on inverrary blvd ,lauderhill,
i came home about a month before the world went crazy regarding the air plane crash with the trade center,
the weather will be cooling down a little now i would think ,those tropical storms every day at about 3pm were new to me,
before that i stayed in AR,i enjoyed AR as i was in a little place called plumberville ,only down side was the bugs and snakes that wanted to eat me lol,
keep me posted on your repair ,as i say ,im waiting for parts,it seems to take forever !!, im very excited to get this running,
one other job im going to get done is it needs a new power transformer ,this unit was imported from japan so runs on 100v,
we use 230v here,i have found a transformer ,the schematic says it runs on 20v ac ,
when i opened it up i found a transformer with a output of 22v ac ,
the options i have are 20v, 21v, 24v ,
i might try 21v ac and see how it goes,
what do you think? i dont like using a step up transformer as it looks abit strange in the wiring and just another thing to go wrong or unplug ,
all the best
mike