Hello all, I recently rebuilt my AMI G-80 amplifier. I replaced all the capacitors and Ive noticed that I am getting a little humming from my speaker and a little squelchy noise from time to time when my records play. Does anyone have any thoughts?
Thanks as always
Jamie
On 1/25/23 10:07, Jamie McElroy via Jukebox-list wrote:
Hello all, I recently rebuilt my AMI G-80 amplifier. I replaced all the capacitors and Ive noticed that I am getting a little humming from my speaker and a little squelchy noise from time to time when my records play. Does anyone have any thoughts?
Does the volume control affect the volume of the hum?
Hi Jay, Thanks for your reply. It doesnt seem to affect it.
On Wed, Jan 25, 2023 at 3:21 PM Jay Hennigan via Jukebox-list < jukebox-list@lists.netlojix.com> wrote:
On 1/25/23 10:07, Jamie McElroy via Jukebox-list wrote:
Hello all, I recently rebuilt my AMI G-80 amplifier. I replaced all the capacitors
and
Ive noticed that I am getting a little humming from my speaker and a
little
squelchy noise from time to time when my records play. Does anyone have
any
thoughts?
Does the volume control affect the volume of the hum?
-- Jay Hennigan - jay@west.net Network Engineering - CCIE #7880 503 897-8550 - WB6RDV
Jukebox-list mailing list Jukebox-list@lists.netlojix.com http://lists.netlojix.com/mailman/listinfo/jukebox-list Searchable Archives: http://jukebox.markmail.org/
On 1/25/23 17:59, Jamie McElroy wrote:
Hi Jay, Thanks for your reply. It doesnt seem to affect it.
Hum unaffected by the volume control is often either bad power supply filtering or heater-to-cathode leakage in the phase splitter or power tubes.
Was there also hum before the rebuild?
I don't know about the hum before the rebuild. I didn't have it working before I rebuilt it. What would you recommend I do? Thank you - Jamie
This file of hum samples might help diagnose the problem:
http://www.fileconvoy.com/dfl.php?id=g693bae6309b156e01000475909cd24afe4142c...
The first is 60hz. It is lower pitched and generally associated with inadequate shielding or heater-cathode leakage in a tube. In an amp, this can be before or after the volume control
The second is 120Hz. This represents either inadequate filtering of the DC supply, or an excessive load on it that exceeds the filtering capacity.
RobNYC
On Wednesday, January 25, 2023, 09:00:04 PM GMT-5, Jamie McElroy via Jukebox-list jukebox-list@lists.netlojix.com wrote:
Hi Jay, Thanks for your reply. It doesnt seem to affect it.
On Wed, Jan 25, 2023 at 3:21 PM Jay Hennigan via Jukebox-list < jukebox-list@lists.netlojix.com> wrote:
On 1/25/23 10:07, Jamie McElroy via Jukebox-list wrote:
Hello all, I recently rebuilt my AMI G-80 amplifier. I replaced all the capacitors
and
Ive noticed that I am getting a little humming from my speaker and a
little
squelchy noise from time to time when my records play. Does anyone have
any
thoughts?
Does the volume control affect the volume of the hum?
-- Jay Hennigan - jay@west.net Network Engineering - CCIE #7880 503 897-8550 - WB6RDV
Jukebox-list mailing list Jukebox-list@lists.netlojix.com http://lists.netlojix.com/mailman/listinfo/jukebox-list Searchable Archives: http://jukebox.markmail.org/
_______________________________________________ Jukebox-list mailing list Jukebox-list@lists.netlojix.com http://lists.netlojix.com/mailman/listinfo/jukebox-list Searchable Archives: http://jukebox.markmail.org/
That can be very helpful. Nice post.
On 1/26/2023 12:54 PM, Chan Gade via Jukebox-list wrote:
This file of hum samples might help diagnose the problem:
http://www.fileconvoy.com/dfl.php?id=g693bae6309b156e01000475909cd24afe4142c...
The first is 60hz. It is lower pitched and generally associated with inadequate shielding or heater-cathode leakage in a tube. In an amp, this can be before or after the volume control
The second is 120Hz. This represents either inadequate filtering of the DC supply, or an excessive load on it that exceeds the filtering capacity.
RobNYC
I have a problem here that I can't work out: The selector arm that raises and lowers the tray takeout lever does not appear to have enough travel distance. For example if I set it so that the top tray is centred on the takeout lever when the star wheel locks the cam in the top position, the lever will then not go low enough to operate the lowest tray when the star wheel is locked in the lowest position. Also the intermediate selections are not centred properly, they are all a bit too high. Compromising the adjustments a bit, I can just about get it to operate - but it is dangerously close to bringing out 2 trays at once in certain positions.
I have already done the following, making little difference - Fitted new roller / bushing inside heart cam, swapped heart cam with another one, swapped star wheel with another one. I have also made sure everything is free to move and well lubricated. I just can't see how there was ever any more vertical movement at the end of selector arm, but clearly there needs to be. What am I missing??
Adrian.
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Does the part that raises and lowers quickly jump up or down a little before attempting to pull the tray out?
On 7/31/2023 9:05 AM, jukeoffice via Jukebox-list wrote:
I have a problem here that I can't work out: The selector arm that raises and lowers the tray takeout lever does not appear to have enough travel distance. For example if I set it so that the top tray is centred on the takeout lever when the star wheel locks the cam in the top position, the lever will then not go low enough to operate the lowest tray when the star wheel is locked in the lowest position. Also the intermediate selections are not centred properly, they are all a bit too high. Compromising the adjustments a bit, I can just about get it to operate - but it is dangerously close to bringing out 2 trays at once in certain positions.
I have already done the following, making little difference - Fitted new roller / bushing inside heart cam, swapped heart cam with another one, swapped star wheel with another one. I have also made sure everything is free to move and well lubricated. I just can't see how there was ever any more vertical movement at the end of selector arm, but clearly there needs to be. What am I missing??
Adrian.
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On 2023/07/31 6:05 a.m., jukeoffice via Jukebox-list wrote:
I have a problem here that I can't work out: The selector arm that raises and lowers the tray takeout lever does not appear to have enough travel distance. For example if I set it so that the top tray is centred on the takeout lever when the star wheel locks the cam in the top position, the lever will then not go low enough to operate the lowest tray when the star wheel is locked in the lowest position. Also the intermediate selections are not centred properly, they are all a bit too high. Compromising the adjustments a bit, I can just about get it to operate - but it is dangerously close to bringing out 2 trays at once in certain positions.
I have already done the following, making little difference - Fitted new roller / bushing inside heart cam, swapped heart cam with another one, swapped star wheel with another one. I have also made sure everything is free to move and well lubricated. I just can't see how there was ever any more vertical movement at the end of selector arm, but clearly there needs to be. What am I missing??
Adrian.
Does it look like the roller is twisted at all? The arm may be warped due to being jammed if so.
If the arm is not twisted then try adjusting it so the top tray is below the center but above the next tray enough to easily clear, and then check that the bottom most tray is still going to be pulled out without the risk of two trays coming out together. I find the adjustment is sometimes the best position is a compromise at both the top and bottom tray.
John :-#)#
Many parts wear over the years and make for sloppy action of that selector system. You didn't mention the bushing inside the slotted end of the actuating lever. The bearing and link assembly will get sloppy, especially the riveted post. I've drilled it out and made new threaded posts to attach with screws. Sounds silly, but be sure you have a tight fitting cotter pin in the take out bar where it connects to the bearing and link assembly. The distance between the shoulder bolt holding the far left end of the actuating lever and the centerline of the selector shaft is critical. If the selector shaft hole in the rear main casting is worn, this distance is increased and you will lose some up and down travel. Check this hole for wear, and also check to see if your shoulder bolt is not bent to the left. Be sure the casting is not cracked or warped anywhere. Be sure that boss around the selector shaft hole has not been broken and soldered in the past. If so, you might look for another casting. You should also make initial adjustments of the take out bar near the center of the stack, either #6 or #18. Be sure the star wheel is not bent and slots are even. Remove the pin holding the star wheel to the heart shaped cam and throw it away. These were drilled/installed per mech and since you've changed cams, that location is no longer valid. The screw holes in the star wheel are big enough to allow adjustment, and a little goes a long way. Be sure your segment gear is adjusted correctly for 23/24 revolution of the selector shaft, remove all record trays, and start the mech free wheeling. Get your hand on the power switch in case two trays come out and get stuck half way. Watch the take out bar as the mech cycles and see where it lines up with each tray. If the take out bar is high on the high number trays, and low on the low number trays, loosen the screws on the star wheel and move it clockwise slightly. If the take out bar is high on low number trays and low on high number trays, move the star wheel counter clockwise. This last bit of info is not in the manual and took me a long time to figure out... Good luck, and let us know what you find. On Monday, July 31, 2023 at 09:30:30 AM EDT, jukeoffice via Jukebox-list jukebox-list@lists.netlojix.com wrote:
I have a problem here that I can't work out: The selector arm that raises and lowers the tray takeout lever does not appear to have enough travel distance. For example if I set it so that the top tray is centred on the takeout lever when the star wheel locks the cam in the top position, the lever will then not go low enough to operate the lowest tray when the star wheel is locked in the lowest position. Also the intermediate selections are not centred properly, they are all a bit too high. Compromising the adjustments a bit, I can just about get it to operate - but it is dangerously close to bringing out 2 trays at once in certain positions.
I have already done the following, making little difference - Fitted new roller / bushing inside heart cam, swapped heart cam with another one, swapped star wheel with another one. I have also made sure everything is free to move and well lubricated. I just can't see how there was ever any more vertical movement at the end of selector arm, but clearly there needs to be. What am I missing??
Adrian.
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