Fhamre
Super Member
Picked up a nice SX-1980 yesterday. It was only 30 minutes away.
Well have it on the bench. Was told that both channels worked but no phono.
Spent a bit of time just reducing the dust level so I could see things.
From what I can see a less than stellar tech recapped the power supply and changed a few transistors.
I haven't accessed the back of the board yet to admire his soldering skills buy I can see what he did to the axials.
I am in no hurry to dive in. I am reading restoration threads and trying to sort out a plan of what needs to be done specifically to the power supply section to make it reliable.The thought of shorting out the outputs keeps me awake at night. I do always use my DBT after any work has been done.
I did my own baseline assessment of the unit. Confirmed two channel audio and no phono. Tuner works but very touchy and not sure if all the tuner features are working but not too concerned at this point.
I was able to get the DC offset from over 500mv down to around 10mv on both channels. But only have bias on the right channel . The left reads 0mv and won't adjust.
I want to focus on the power supply first. Not a circuit whiz/artist. More of a paint by numbers guy.
I have the service manual.Have restored a lot of gear including at least 3-1250's and a 1080. But its been awhile.
Would appreciate any advice. Can one disconnect the two driver boards when testing the power supply?
What bulb wattage would you recommend in the dbt?
I will keep doing research. I have read about EW's current source modification and Marks LY1 24V recommendation.
Well have it on the bench. Was told that both channels worked but no phono.
Spent a bit of time just reducing the dust level so I could see things.
From what I can see a less than stellar tech recapped the power supply and changed a few transistors.
I haven't accessed the back of the board yet to admire his soldering skills buy I can see what he did to the axials.
I am in no hurry to dive in. I am reading restoration threads and trying to sort out a plan of what needs to be done specifically to the power supply section to make it reliable.The thought of shorting out the outputs keeps me awake at night. I do always use my DBT after any work has been done.
I did my own baseline assessment of the unit. Confirmed two channel audio and no phono. Tuner works but very touchy and not sure if all the tuner features are working but not too concerned at this point.
I was able to get the DC offset from over 500mv down to around 10mv on both channels. But only have bias on the right channel . The left reads 0mv and won't adjust.
I want to focus on the power supply first. Not a circuit whiz/artist. More of a paint by numbers guy.
I have the service manual.Have restored a lot of gear including at least 3-1250's and a 1080. But its been awhile.
Would appreciate any advice. Can one disconnect the two driver boards when testing the power supply?
What bulb wattage would you recommend in the dbt?
I will keep doing research. I have read about EW's current source modification and Marks LY1 24V recommendation.