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Vintage DD turntables. Are we living dangerously?

I have just acquired a 32 year old JVC/Victor TT-101 DD turntable after having its lesser brother, the TT-81 for the last year.
TT-101
This is one of the great DD designs made at a time when the giant Japanese electronics companies like Technics, Denon, JVC/Victor and Pioneer could pour millions of dollars into 'flagship' models to 'enhance' their lower range models which often sold in the millions.
Because of their complexity however.......if they malfunction.....parts are 'unobtanium'....and they often cannot be repaired.
halcro
dover
2,337 posts
 
There is only one way to "redo" old solder joints, and that is to completely strip and clean off ALL of the old solder from both the eyelet and the component. This is incredibly tedious and time consuming. Some folk just wave a wand, melt the original solder and then add more solder - this is a recipe for disaster.
downunder
1,329 posts
 
Great new Halcro!!

But seems like those JVC techs might have been cutting corners back in the day :-)

touch wood, but the Pioneer Exclusive turntable did not have any corners cut.
I guess that is why they offered lifetime servicing for all Exclusive hifi gear.

Unfortunately the hifi gear might outlive Pioneer corporation.
halcro's avatar
halcro OP
2,664 posts
 
Thanks Shane,
Not sure if corners were cut or it's simply an aging characteristic of solder?
I think it's the number of joints and the sheer complexity of their locations plus the triple layer stack of PCBs which must flex whenever they are handled for servicing that is the real problem...?
totem395
390 posts
 
Halcro

I think it's the number of joints and the sheer complexity of their locations plus the triple layer stack of PCBs which must flex whenever they are handled for servicing that is the real problem.

You hit the proverbial nail on the head, the hole bugaboo regarding DD IC failures {in this case} should be finally put to rest.
banquo363
371 posts
 
I searched through my communications with my tech when he was servicing my tt 101. Below are some pertinent quotes on the construction of the boards and how he went about fixing the table:

--There were no bad parts, just bad connections. I ended up resoldering all the feed thru eyelets, then flipping the board and removing the solder with a sucker, then resoldering them with much less solder. They all look pretty clean now. I know other companies that used the eyelet method had reliability problems. For some reason the solder cracks around the eyelets, probably related to different coefficients of thermal expansion.

--Besides I took a lot of solder out of those eyelets. The issue is the eyelets are hollow so they don’t fill with solder. The hot air insides always bubbles the solder out. I put just a bit around the edges and then cleaned the flux with acetone.

--The PCB is two sided but without plated through holes. It looks like they put eyelets in and then solder on both sides. I found one that was open but by the time I pulled the PCB it was connecting. I resoldered it and now the 45 light comes on and that speed works. The 33 light never comes on so I think there is something wrong with that flip flop. It is made of all discrete transistors so it is really hard to figure out the logic flow.

--I’m always amazed when someone would design a product as complex as this, with a high price, and not spring for a plated thru board. It boggles the mind that they would have relied upon these eyelets which are labor intensive.
Hope it helps someone.
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