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Turntable volume low compared to radio. Preamp trouble?

yaztron

yaztron

New Member
Hey all,

This is my first post so excuse me if I am posting in the wrong place!

I have a Fisher 201 that I've owned since 1972. I've noticed lately that the turntable input volume isn't level with radio volume anymore. Lately when listening to records with my Pioneer DL12, the volume has been very low, so I hooked up my son's U-Turn turntable (with no preamp in table) but no that made no difference.

Performed some pre-checks on the preamp. The right output from IC01 measured 11.0, but the schematic says 11.6. The left output from IC02 measured 10.6. Could this be a problem with the preamp? B+ measured 22.2 and schematic says 22.5.

Any leads or ideas? Thank you!
 
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Welcome aboard Yaz
First I think I would try to clean your selector switch SW5.
 
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Welcome to the Fisher "nut house". Allow for 10% variance in voltages due to component tolerances wear, and different line voltages. a 1/2 or 2 volt on these isn't anything to worry about. Has the 201 been restored or is it still Cherry? You could have transistors or caps that are failing. Power Supply gets rebuilt 1st. Once all the P.S. output voltages are fine most everything else falls in line and quite a few "gremlins" leave. My copy of the S.M.( https://www.hifiengine.com/manual_library/fisher/201.shtml ) say B+ on the 4042 preamp is 24.5V to the IC's. Check all your P.S. voltages and report back. And need your line (wall) voltage.
 
larryderouin said:
Welcome to the Fisher "nut house". Allow for 10% variance in voltages due to component tolerances wear, and different line voltages. a 1/2 or 2 volt on these isn't anything to worry about. Has the 201 been restored or is it still Cherry? You could have transistors or caps that are failing. Power Supply gets rebuilt 1st. Once all the P.S. output voltages are fine most everything else falls in line and quite a few "gremlins" leave. My copy of the S.M.( https://www.hifiengine.com/manual_library/fisher/201.shtml ) say B+ on the 4042 preamp is 24.5V to the IC's. Check all your P.S. voltages and report back. And need your line (wall) voltage.
Click to expand...

Thank you. I will have the readings tomorrow
 
I had replace Q1 about 3 years ago.
Here are the power readings.
A, 15.22 vdc
B. 30.94 vdc
C. 50.40 vdc
E. 19.35 vac
F. 19.14 vac
larryderouin said:
Welcome to the Fisher "nut house". Allow for 10% variance in voltages due to component tolerances wear, and different line voltages. a 1/2 or 2 volt on these isn't anything to worry about. Has the 201 been restored or is it still Cherry? You could have transistors or caps that are failing. Power Supply gets rebuilt 1st. Once all the P.S. output voltages are fine most everything else falls in line and quite a few "gremlins" leave. My copy of the S.M.( https://www.hifiengine.com/manual_library/fisher/201.shtml ) say B+ on the 4042 preamp is 24.5V to the IC's. Check all your P.S. voltages and report back. And need your line (wall) voltage.
Click to expand...
 
Ok. All are consistantly low and within the +/- values. The P.S. is running a little on the low side but well within spec. That's ok. Get hold of DeOxit D5 (or DN5) spray. Open it up and hit every switch, pot, (if it goes in-out, up-down or Round & Round, it gets DeOxit.) let sit for 30 minutes, then give it a light spritz and go to town exercising all switches and pots 40-50 times each (no need for spinach here.:)) Get some CRC 2-26 Electronics Lubricant (Home Depot in electrical dept.) and lube all the pots and switches you just cleaned. Test again.

The 201 is full of 2SC458's (Low noise when new and have a bad history of getting noisey now.) 2sc1845 is recommended replacement transistor.
 
larryderouin said:
Ok. All are consistantly low and within the +/- values. The P.S. is running a little on the low side but well within spec. That's ok. Get hold of DeOxit D5 (or DN5) spray. Open it up and hit every switch, pot, (if it goes in-out, up-down or Round & Round, it gets DeOxit.) let sit for 30 minutes, then give it a light spritz and go to town exercising all switches and pots 40-50 times each (no need for spinach here.:)) Get some CRC 2-26 Electronics Lubricant (Home Depot in electrical dept.) and lube all the pots and switches you just cleaned. Test again.

The 201 is full of 2SC458's (Low noise when new and have a bad history of getting noisey now.) 2sc1845 is recommended replacement transistor.
Click to expand...

Thank you for your response. I figures there was no problem with the voltages. I just picked up some CRC QD- Contact Cleaner from Home Depot. Would you recommend that or I can get DeOxit?
 
DeOxit for the pot and switches. It loosens the crud on the contacts so that friction from exercising them will scrub the contact points clean. But hold on to the crc, its good for cleaning the variable cap (fins) on the tuner.
 
larryderouin said:
DeOxit for the pot and switches. It loosens the crud on the contacts so that friction from exercising them will scrub the contact points clean. But hold on to the crc, its good for cleaning the variable cap (fins) on the tuner.
Click to expand...

DeOxit is on order! Thanks!
 
A note: A 201 was my first Fisher I owned, and a gateway drug. Also was a very sweet sounding receiver, and the tuner section's among the best. Avery and his engineers did a great job on designing it. Best wishes on the restoration. A 400 which belonged to my late Stepdad, got me hooked on Fisher's musical, sweet sound. I love a good Fisher.
 
You'll probably end up rebuilding the Pre-Amp. But 1st double check the wiring from the Phono RCA Jacks to the Preamp board. Pins 4A and 4D. Check R01, 02, 11, & 12. Lift one leg and check out of circuit. Replace if more than 5% out of tolerance.

As it has IC's, just replace the 5 electrolytics. Good bet they are dried out and not working. 4 x 10uf 50V UKL series Nichicon, and 1 47uf 63V UPW or UHE caps.

Part #'s and prices are Mouser as of this post.

10uf 50V UKL 647-UKL1H100KDDANA ($0.43ea) x4
47uf 63V UPW 647-UPW1J470MPD1TD ($0.45ea)x1 (Note: According to the manual, this cap is on the solder side of the board.)

Shipping is gonna be more than the parts. So count up the 2sc458 transistors and replace them with KSC1845FTA. They get noisy with Age. Not a case of If, but WHEN! pre-emptive strike is best for these.

512-KSC1845FTA ($0.28ea price goes down at quantity of 10 to $0.21 IIRC) 4 on the Control Amp, 7 on the Multiplex (not recommended to change unless you can align the MPX). Also 3 on the AM/FM IF Meter board (again don't mess with). The 1845 legs are oriented LEFT TO RIGHT, Flat facing you legs DOWN as E-C-B. the 2sc458 is B-C-E. Exact opposite.
 
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Just for sh*t's and giggles, check the voltages on the IC's on the preamp board. Specifically pins 1, 2, 3, 5, 6, 7. compare with schematic values. Report them next post.
 
Thanks for the reply.
IC01 Pin 6, 11.01vdc
IC02 Pin 6, 10.6vdc (1v low)
Pin 4H and 4K, 22.2vdc but then again, the PS is low but in spec. I gotta open her back up the rest of the readingd. Are the IC's 01 and 02 available?

Just want to say I used DeOxit on a 70's Sony table top AM-FM. Works like bran new!! Great stuff. Kinda oily but works. Thanks again!
 
it's very typical for a phono section to be lower volume than the other outputs. I realize you stated this is different from before, have you changed the cartridge recently? Is the SQ on phono worse than before, if not could it possibly just be memory error?
 
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