Panasonic SG-J500L, Capacitor and belts Change

[wayne916]

Arrived with loud buzzing sound. Now Fully working.
Saved from the dump, cleaned, serviced, new belts and complete electrolytic cap change.

Belts (Approx.)
Turntable = Folded length 306mm x thickness 0.6m x 5mm,
Cassette = Folded length 100mm x thickness square 1.1mm, cut length 203mm.
Electrolytic capacitors required
0.1uF 50v x3
0.22uF 50V x1
1uF 50v x6
2.2uF 50v x1
10uF 16v x6
47uF 6.3v x1
47uF 10v x8
100uF 16v x2
100uF 10v x2
220uf 16v x1
330uf 10v x1
470uf 10v x2
470uf 16v x1
2200uf 16v x1

 

[Brutus442]

I don't recall ever seeing this model. Great job on the restoration!

 

[caution]

Another one saved, nice work!
I know it's not easy to find published lengths for belts, but using the old worn out ones as a reference is dodgy, you'd be better off measuring the belt path with some string and knocking off a couple percent.
I was curious and looked up their part numbers from the service manual and found the turntable belt is supposed to be about 570mm (285 folded) so if you notice any issues that might be why

 

[hopey]

Did you test the caps you removed? I have found the problem with these boxes is the Function switches.

 

[wayne916]

While testing the capacitors most of the lower value's between 1uf and 10uf had a high ESR and were wildly out of spec for the capacitance value as stated on the capacitor body, there were no signs of swelling or leakage with any of the capacitors. The SG-500L were made in the early 1980's, I think it is good practice to change out the Electrolytic caps after 30 plus years especially if they used the early Rubycon manufactured capacitors!! its only a question of time before the capacitors fail, while the unit is open and for the small component cost, well worth doing.

Electrolytic Capacitor Lifetime is related to time and temperature, if the temperature increases when in use the capacitor lifetime is reduced.
30 to 40 years life is not uncommon for electrolytic capacitors kept at the manufactures recommended operating temperature.
Excessive ESR dose not usually cause a catastrophic failure, the Capacitor ESR can increase as the electrolyte dries out.
In the case of a power supply that would cause excessive ripple and probably some resulting hum.

 

[Tinman]

Congrats.
It's always a good feeling reviving something that was headed to the dump/landfill.
I've found the Panasonic caps tend to leak more than the other brands used on the better name brand boxes back then.
I've had at least 6 Panasonic boxes and replaced numerous leaking caps in every one.

 

[BoomboxLover48]

Congrats.
It's always a good feeling reviving something that was headed to the dump/landfill.
I've found the Panasonic caps tend to leak more than the other brands used on the better name brand boxes back then.
I've had at least 6 Panasonic boxes and replaced numerous leaking caps in every one.

If the electronic gadget was kept in a climate-controlled atmosphere electrolytic capacitors lasted more. All my Panasonics came from good homes and had no issues with capacitors and had a few SONY models that came from some parts of world with hot weather conditions all have issues with leaky capacitors. The black speaker cone paper turned brown, and color faded cabinet showed exposure to sun a lot. So, I believe it has more to do with how it was exposed to the storage conditions.

 

[Tinman]

If the electronic gadget was kept in a climate-controlled atmosphere electrolytic capacitors lasted more. All my Panasonics came from good homes and had no issues with capacitors and had a few SONY models that came from some parts of world with hot weather conditions all have issues with leaky capacitors. The black speaker cone paper turned brown, and color faded cabinet showed exposure to sun a lot. So, I believe it has more to do with how it was exposed to the storage conditions.

I have no idea what conditions the ones I owned came from so you may be right.
I found both woofer magnets had fallen off my one 7700 when it arrived.
I don't remember if I had any issues with the caps just that they had corrosion on their legs so I changed them out.
That being said, I've refurbished more than 30 boxes over the last 5 or 6 years.
I assume they didn't all come from climate controlled atmospheres especially with the terrible shape of most of them.
Other than the Panasonics and Sanyos, the majority of boxes have had Rubycons and I've found very few of those caps visually leaking.
Even the 6 Realistics I've owned with mostly cheaper caps (I think most were Marcon brand) had very few leaky ones but a lot of those were out of spec as opposed to the Rubycons.