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Pot meters for Marantz SR430

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mcs51mc

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I need new pot meters for volume and balance for my Marantz SR430 receiver/amplifier.
I thought to solder the old ones out and replace them by new ones from the electronic shop but..... these are weird pot meters :(

The volume pot meter has 8 connections
The balance pot meter has 4 connections

I measured the resistance between different connections, results can be found in the attached files. Want the original xls file? PM me and and mail them to you.

Since I never used the balance pot meter (always in the middle) I replaced it by two 100k resistors between connections A2 and B2. The centre point is connected to both A1 and B1.

My questions are:
1) Any idea where I can buy new pot meters
2) Is it possible to replace these potmeters by Dallas DS1809 (**broken link removed**) pot meters in combination with … …

Thanks a lot for your ideas
 

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Generally you need to buy the pots as specific spare parts for that model - it's common to have extra connections on the volume control for loudness compensation, which is why they often have 8 connections rather than 6.
 
hi,
>>
My questions are:
1) Any idea where I can buy new pot meters
2) Is it possible to replace these potmeters by Dallas DS1809 (**broken link removed**) pot meters in combination with … …


The Maxim pots have only 64 discrete steps from min to max, also they are linear pots, the volume controls are normally logramithic pots.

Can you tell us whats wrong with the existing pots???
 
Thanks for that response but I'm not completely helped, so allow me to investigate a little more :)

Do you know a place where I can buy these pot meters?

Attached you can find part of the schematic diagram for that model. Like you said Nigel the extra connection (in the middle of the pot meter) goes to the loudness switch.
The LS switch is shown in it’s off position, so only resistors RS01 and RS02 are used.
All other components around the LS switch are useless because or shortened or not connected at one side.
How would you modify this circuit so that “standard” components can be used?

CS07 and CS08 goes to the integrated amplifier STK4843 and a pop-noise canceller circuit AN6135 (just learned such things exists :) ).
 

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ericgibbs said:
The Maxim pots have only 64 discrete steps from min to max, also they are linear pots, the volume controls are normally logramithic pots.
I thought 64 steps are enough to regulate volume :( Isn't it so?
The log thing is something I learned at school long time ago (audio equals log pot meters), but if you look at the Excel sheet you don't get straight line with a log Y-axis, upper graph (log values on log scale should result in a straight line).
With a lineair Y-axis, lower graph, it's almost straight except for the first and last points.
So I'm still not sure if the volume pot is a lin or log one :(

ericgibbs said:
Can you tell us whats wrong with the existing pots???
Actually I have two problems with them:
First, sometimes the right channel suddenly plays less loud than the left one or even fade completely. Just moving the balance pot meter a litlle left, right and place it in the middle again solves the problem. That's why I remplaced it with the two 100k resisitors. Didn't encounter the problem since then (3 days).
Second problem is noise and cracks when I regulate the volume pot meter (over 20 years of age remember). I already sprayed with contact cleaner but it's ok only for some time, then the problem is back again.

Now I try to solve the problem once and for all :)
So thanks for all possible inputs...
 
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hi,
Ive looked thru places that may have the spares, but its a 'vintage' piece of kit. Lots of the SR430 at eBay...

Nearest I could find that may stock MARANTZ parts is www.ersatzteilblitz.de

I'll keep an eye open for any hits, but think my chances are slim.

The problem with DS1809 is its digitally controlled.

EDIT:
Contact cleaner works for a while as you say, have you tried a light oil, 3 in 1, just a spot!.
I have found that it cleans and works much longer than Servisol contact cleaner.
 
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ericgibbs said:
Contact cleaner works for a while as you say, have you tried a light oil, 3 in 1, just a spot!.
I have found that it cleans and works much longer than Servisol contact cleaner.

WD40 works far better than contact cleaner, I've been using it exclusively for 25 years plus!. Contact cleaner removes the pots (or switches) internal lubrication, WD40 cleans and re-lubricates.

As for loudness taps?, just ignore them!.
 
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