Cody Shive
New Member
New thread dedicated to the Pioneer CT-F950 Adjustments, both mechanical and electronic.
Pioneer CT-F950 Adjustments
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Cody Shive
New Member
The first post here is to see if anyone knows what the POT on RWG-103, VR501, calibration should be?
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rojoknox
Well-Known Member
Greetings from RojoLand!
VR501 is marked on the main schematic page (12.3) as "Clock Freq. Adj." There should be no reason to mess with this. It adjusts the voltage on pin 13 of IC501. Have read through the discussion of the control circuit twice and I find no mention of VR501, IC501 pin 13, or how that control is to be adjusted. There is a test point on IC501 pin 13, but with no specification given for the voltage, we have no way to know what it's supposed to be. I really hope you didn't diddle that pot!
Take care,
—
J. E. Knox "The Victor Freak"
VR501 is marked on the main schematic page (12.3) as "Clock Freq. Adj." There should be no reason to mess with this. It adjusts the voltage on pin 13 of IC501. Have read through the discussion of the control circuit twice and I find no mention of VR501, IC501 pin 13, or how that control is to be adjusted. There is a test point on IC501 pin 13, but with no specification given for the voltage, we have no way to know what it's supposed to be. I really hope you didn't diddle that pot!
Take care,
—
J. E. Knox "The Victor Freak"
You're a brave man, those Pioneer units are quite complex and mostly problematic by now. Just finished up the transport section/belts/clutch on a CT-F1000 a couple weeks back, wasn't much fun tbh.
MRL_Audio
RIP 2022
@Cody Shive - I came here thinking you were going to be sharing some key adjustments for this deck. Seems not the case. If you are looking for adjustments, suggest you search for a service manual on-line and start from there. In addition are the 100's of posts on this popular deck here and elsewhere. Is there some specific adjustment you are trying to determine or just fishing?
Check out the attached picture I took from a perfectly operating CT-F1250. Measured at the TP near VR501. The frequency is 13.0569 MHZ. Should be close enough as this unit was untouched.The first post here is to see if anyone knows what the POT on RWG-103, VR501, calibration should be?
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Cody Shive
New Member
Thanks, Neil! That's what I was looking to find. No manuals that I have found specified this, although I did confirm rohoknox's mention above. Overall, I've found these decks to be easily serviceable, from the mechanism to the discrete electronics. Occasionally, I'll find a bodge (like with the CT-F900 control board that stops a feedback in the logic circuit from randomly going into REW), and have to figure it out myself. All of these adjustments, I suspect, came out in some sort of service campaign or bulletin in the 70s or 80s; but those documents are likely long lost.
And, for those thinking there are qualified personnel out there, I was one of them in the 80s. I just abandoned that career for computers, and never looked back. It's nice to see there are still folks out there who are servicing these and share (as I do in my YouTube videos) what they've done and why. It helps the rest of us remember what they'd long forgotten.
And, for those thinking there are qualified personnel out there, I was one of them in the 80s. I just abandoned that career for computers, and never looked back. It's nice to see there are still folks out there who are servicing these and share (as I do in my YouTube videos) what they've done and why. It helps the rest of us remember what they'd long forgotten.
