Sad Sansui...

Alamo308

Alamo308

Member
:( My beautiful QRX-7001, bought from BX new in Korea 43 years ago, rebuilt from ground up several years ago by a chap in Pennsylvania, has suddenly started its old snap, crackle, and pop again, with every movement of the volume knob, or just randomly and very loudly during music listening, from any source. Very sad. I guess maybe it's finally time to convert it to a very expensive door stop?
QRX-7001_reduced_zpszdn8v7il.jpg
 
From what you've said, it actually seems like it may be just dirty control, especially the volume control.

A cleaning with deoxit may fix you right up.
 
If it does it just randomly, it's most likely a small signal transistor going intermittent. They do that some times.
More often than not, it is a part known for becoming sketchy over time, and most general repair shops will miss things like that.
 
Yep, the deoxit worked! Couple shots right on to the volume pot shaft, and it now works clean and quiet. Thanks to all.
I used Radio Shack's Cleaner and Lubricant.
 
Yer not gonna like this. That Radio Shack cleaner and lube will eventually turn into a waxy substance that no amount of contact cleaner will ever remove. Best bet is to go buy a can of CRC no residue electronic cleaner, available at any car parts house and hose that RS stuff out of there. Then go back in with real De-Oxit (I prefer DN5 for pots).
 
tarior said:
Yer not gonna like this. That Radio Shack cleaner and lube will eventually turn into a waxy substance that no amount of contact cleaner will ever remove. Best bet is to go buy a can of CRC no residue electronic cleaner, available at any car parts house and hose that RS stuff out of there. Then go back in with real De-Oxit (I prefer DN5 for pots).
Click to expand...

Yeeuck! Thanks for that heads up. Yes, I'm a nug.
Off we go to AutoZone...
 
AFAIK, RS sells small cans of real CAIG De-Oxit. Or at least they used to.
 
Do not use Deoxit DN5 for pots, it washes the lube away and your pots will wear out, DN5 has no lubricating properties.
Use Faderlube F5 on pots sliders ect...
Use Deoxit DN5 on switches.
 
tarior said:
DN5 is plenty oily. Spray some on your fingers.
Click to expand...

I disagree, its for switches and contacts, not faders or Pots.

I am a full time tech. I use these products all the time, and I have seen the damage done when the wrong product is used.
 
kevzep said:
I am a full time tech.
Click to expand...
You and me both. Ever notice that pots are dry from the factory?
I will add that there is nothing wrong with using Faderlube. It should be noted that CAIG actually recommends Gold or Shield as a follow up to De-Oxit.
I used to use Faderlube on everything until I realized the D(N)5 was plenty oily, and adding F100 just added to the dust attracting oily creep.

I hate opening up a unit where a previous tech has used LPS or something similar, and it looks like Exxon Valdez in there.
 
Last edited:
I need to correct my previous post, or add more information to it. Carbon pots do need additional lube, and applying deoxit to them is a matter up for debate. Sadly, it seems that truly carbon safe contact cleaners are no longer available. Conductive plastic pots really don't need lube, but it seems to help to have D100 (what's left after the carries of D5/DN5 evaporate) or G100 in them..especially when they are older.
 
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