Hi,
I currently restore a GOLDMUND Mimesis 3 amplifier, and I have to change this variable resistor (see attached photo):
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The following references are written on the part:
64Y 201
R601
Do you know what is the exact value: 200ohms, 600ohms ?
Thank you
P.S.: I know that I could measure it after desoldering, but as I am about to place an order for the other parts, I prefer to include this R with the order...
I currently restore a GOLDMUND Mimesis 3 amplifier, and I have to change this variable resistor (see attached photo):
The following references are written on the part:
64Y 201
R601
Do you know what is the exact value: 200ohms, 600ohms ?
Thank you
P.S.: I know that I could measure it after desoldering, but as I am about to place an order for the other parts, I prefer to include this R with the order...
Hi,
I currently restore a GOLDMUND Mimesis 3 amplifier, and I have to change this variable resistor (see attached photo):
[/url][/IMG]
The following references are written on the part:
64Y 201
R601
Do you know what is the exact value: 200ohms, 600ohms ?
Thank you
P.S.: I know that I could measure it after desoldering, but as I am about to place an order for the other parts, I prefer to include this R with the order...
Seems 200 ohms, that is the typical way of labelling. You can measure without desoldering that will give you a close enough indication.
Jan
Thak you Jan , I also believe it is this value...
If I measure it without desoldering, the measured value should normally be impacted by the circuit it is connected to, shouldn't it ??
If I measure it without desoldering, the measured value should normally be impacted by the circuit it is connected to, shouldn't it ??
Hardly. The measurement current is small, and even if it isn't absolutely accurate, it's enough to see if it is 200R or 600R. Did you try?
BTW If this is connected as a rheostat (wiper connected to one side) make sure to record the position, then turn it to one side fully, then measure, then reset to value ;-)
Jan
Not yet, but I will tomorrow : it has been a nightmare to open this device, but I finally succeeded...
Sometimes I believe that the manufacturer has done everything possible to make the maintenance as difficult as possible....
Because I used to work with an engineer for restoring vintage devices, and he cannot get the amp stable because of a faulty VR.
I will change them, as I used to do these tasks very often...
Thank you
That is extremely unusual. You should be prepared for the fact that there actually is another issue.
Again, it is a no-brainer to verify if the VR still works as it should with a simple resistance meeting. Measure the resistance while turning it will very quickly show if there is a short or open.
Jan
Again, it is a no-brainer to verify if the VR still works as it should with a simple resistance meeting. Measure the resistance while turning it will very quickly show if there is a short or open.
Jan
Why do you think that? When you said, that there was a stability problem, what kind? Thermal? Oscillations?
Jan
Here are the measurement I performed this morning (without desoldering):
LEFT channel:
pin1 -> pin2 = 122 ohms
pin1 -> pin3 = 219 ohms
RIGHT channel:
pin1 -> pin2 = 113 ohms
pin1 -> pin3 = 202 ohms
So this let me think that this variable resistor is 200 ohms...
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Hi
Mark is correct. There are build threads for this good old amplifier here on diyaudio.
That also shows a 200 ohm'ish trim for offset adjustment.
Mark is correct. There are build threads for this good old amplifier here on diyaudio.
That also shows a 200 ohm'ish trim for offset adjustment.
I have this schematics in my collection. The file name refers to Goldmund Mimesis 3.
Attachments
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On the schematic posted by forr just after your reply , the variable resistor is 200 ohms, not 220 ohms.
I have bought and received 200 ohms variable resistors and when I have time to desolder the original ones, I will measure them (to tune the new ones to the same value than the original): I hope that I can use the 200ohms resistors that I have received !??
Thanks
trimmers are usually 10/20/50 scale, not E12, but people often assume its 10/22/47 scale - for almost any use of a trimmer the value is not crucial, since it can be varied or is used as a divider - substitute 220 for 200 or vice versa - remember tolerances can be +/-20% anyway.