Bubba
:I'm back again. Radio side sounds awsome. Little to ZERO hum. Had the Shure Crystal P90S Phono cartridge rebuilt by westech services and put it in. Phono is there but hums too much with respect to audio.. what are the suspect things to get rid of it or are they all this bad? I did all the filter caps a few years back maybee 6 years ago..
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:Bubba
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:I'm back again. Radio side sounds awsome. Little to ZERO hum. Had the Shure Crystal P90S Phono cartridge rebuilt by westech services and put it in. Phono is there but hums too much with respect to audio.. what are the suspect things to get rid of it or are they all this bad? I did all the filter caps a few years back maybee 6 years ago..
:
:Bubba
:
So take amplifier hum out of question. Amplifier sounds great.
It is definatly coming from the Phono. To be more specific the section going to the Shure cartridge outside the chassis. When I short across hot and black on the stylus hum dissapears totally as does signal obviously like it should..
When I short the HOT(red)from the phono cartridge to the base of the record player or (ground) where the shilding is also connected, hum goes away drastically and the set sounds great. volume is normal level when turn up the volume dial. When hot is not shorted to base of record player volume is much much higher (too hot) and hum is very prominent due to the very hot signal and I have to keep the pot almost off unacceptable. I can leave the hot to base of the record player base but why do I need to do it? The schem says only the the Shield should be going the the record base. When I short the cold form the shure cartridge it does not fix it. Only the hot..
Why would this be?
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:Sir Bubba . . . . .
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:The first thing coming to mind after seeing that the set only has that 7C6 triode as initial audio amplification . . . .
:Was if the cartrige rebuild has resulted in high enough output with the new unit ?
:
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:Does it seem to offer more than adequate volume output when cranked up.?
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:To trouble shoot the HUMMMM pick up situation and confirm if it is phono related pick up in nature . . . do this:
:
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:Note the use of two shielded cable runs . . . one related to the path to the turntable and the second related to the changer/tone arm area aspect.
:
:
:If you initially have the volume control set to mid position, that would then be just exhibiting the amps created background noise.
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:The noise is not present at that position . . . is it ?
:If so, the humm pickup problem would not be phono wiring related.
:
:
:If you will then advance the volume to max . . . (with no record playing) . . . you want to see how much backgriund noise there is.
:
:
:If any is present use a small plastic handled mini screwdriver to short across the very end of that first shielded cable run.
:
:
:If a noise was present and it abated on shorting across that line, your hum pick up is on the second shielded line run.
:
:
:Short across the end of the second shielded cables run . . at the cart . . .run and see if the noise disappears .
:
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:ZUJ'ing and waiting to see what your actual findings were . . . .
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:73's de Edd
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::I'm back again. Radio side sounds awsome. Little to ZERO hum. Had the Shure Crystal P90S Phono cartridge rebuilt by westech services and put it in. Phono is there but hums too much with respect to audio.. what are the suspect things to get rid of it or are they all this bad? I did all the filter caps a few years back maybee 6 years ago..
::
::Bubba
::
:
:
Does anyone have the ACTUAL schematic for this 46-1201 122 version. With the 50Y6 and no choke??
THis will likely explain it. If someone has this I will rewire it properly.
:OK well. Like I said when on Radio hum is fine. Just faint filter PS hum. very reasonable.
:
:So take amplifier hum out of question. Amplifier sounds great.
:
:It is definatly coming from the Phono. To be more specific the section going to the Shure cartridge outside the chassis. When I short across hot and black on the stylus hum dissapears totally as does signal obviously like it should..
:
:
:When I short the HOT(red)from the phono cartridge to the base of the record player or (ground) where the shilding is also connected, hum goes away drastically and the set sounds great. volume is normal level when turn up the volume dial. When hot is not shorted to base of record player volume is much much higher (too hot) and hum is very prominent due to the very hot signal and I have to keep the pot almost off unacceptable. I can leave the hot to base of the record player base but why do I need to do it? The schem says only the the Shield should be going the the record base. When I short the cold form the shure cartridge it does not fix it. Only the hot..
:
: Why would this be?
:
:
:
:
:
:
:
:
:
:
:
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::Sir Bubba . . . . .
::
::
::The first thing coming to mind after seeing that the set only has that 7C6 triode as initial audio amplification . . . .
::Was if the cartrige rebuild has resulted in high enough output with the new unit ?
::
::
::Does it seem to offer more than adequate volume output when cranked up.?
::
::
::To trouble shoot the HUMMMM pick up situation and confirm if it is phono related pick up in nature . . . do this:
::
::
::Note the use of two shielded cable runs . . . one related to the path to the turntable and the second related to the changer/tone arm area aspect.
::
::
::If you initially have the volume control set to mid position, that would then be just exhibiting the amps created background noise.
::
::
::The noise is not present at that position . . . is it ?
::If so, the humm pickup problem would not be phono wiring related.
::
::
::If you will then advance the volume to max . . . (with no record playing) . . . you want to see how much backgriund noise there is.
::
::
::If any is present use a small plastic handled mini screwdriver to short across the very end of that first shielded cable run.
::
::
::If a noise was present and it abated on shorting across that line, your hum pick up is on the second shielded line run.
::
::
::Short across the end of the second shielded cables run . . at the cart . . .run and see if the noise disappears .
::
::
::ZUJ'ing and waiting to see what your actual findings were . . . .
::
::
::
::
::
::
::
::
::73's de Edd
::
::
::
::
::
::
::
::
:::I'm back again. Radio side sounds awsome. Little to ZERO hum. Had the Shure Crystal P90S Phono cartridge rebuilt by westech services and put it in. Phono is there but hums too much with respect to audio.. what are the suspect things to get rid of it or are they all this bad? I did all the filter caps a few years back maybee 6 years ago..
:::
:::Bubba
:::
::
::
:
:
I figured it out.. I had the shield and audio revesed coming from the chassis. must have done that along time ago.
That would explain it.
Never heard this thing before with 0 hum as I always had it backwards I guess. Awsome!!
That westech guy did an awsome job.
Bubbs
:Wait a second... I forgot. My 46-1201 is the freako model. Likely I used the schematic for the other one. and wired this like IT just as I did the antenna that cost me a week or more.
:
:Does anyone have the ACTUAL schematic for this 46-1201 122 version. With the 50Y6 and no choke??
:
:THis will likely explain it. If someone has this I will rewire it properly.
:
:
:
:
:
::OK well. Like I said when on Radio hum is fine. Just faint filter PS hum. very reasonable.
::
::So take amplifier hum out of question. Amplifier sounds great.
::
::It is definatly coming from the Phono. To be more specific the section going to the Shure cartridge outside the chassis. When I short across hot and black on the stylus hum dissapears totally as does signal obviously like it should..
::
::
::When I short the HOT(red)from the phono cartridge to the base of the record player or (ground) where the shilding is also connected, hum goes away drastically and the set sounds great. volume is normal level when turn up the volume dial. When hot is not shorted to base of record player volume is much much higher (too hot) and hum is very prominent due to the very hot signal and I have to keep the pot almost off unacceptable. I can leave the hot to base of the record player base but why do I need to do it? The schem says only the the Shield should be going the the record base. When I short the cold form the shure cartridge it does not fix it. Only the hot..
::
:: Why would this be?
::
::
::
::
::
::
::
::
::
::
::
:::
:::
:::
:::
:::
:::
:::
:::
:::
:::
:::
:::
:::
:::Sir Bubba . . . . .
:::
:::
:::The first thing coming to mind after seeing that the set only has that 7C6 triode as initial audio amplification . . . .
:::Was if the cartrige rebuild has resulted in high enough output with the new unit ?
:::
:::
:::Does it seem to offer more than adequate volume output when cranked up.?
:::
:::
:::To trouble shoot the HUMMMM pick up situation and confirm if it is phono related pick up in nature . . . do this:
:::
:::
:::Note the use of two shielded cable runs . . . one related to the path to the turntable and the second related to the changer/tone arm area aspect.
:::
:::
:::If you initially have the volume control set to mid position, that would then be just exhibiting the amps created background noise.
:::
:::
:::The noise is not present at that position . . . is it ?
:::If so, the humm pickup problem would not be phono wiring related.
:::
:::
:::If you will then advance the volume to max . . . (with no record playing) . . . you want to see how much backgriund noise there is.
:::
:::
:::If any is present use a small plastic handled mini screwdriver to short across the very end of that first shielded cable run.
:::
:::
:::If a noise was present and it abated on shorting across that line, your hum pick up is on the second shielded line run.
:::
:::
:::Short across the end of the second shielded cables run . . at the cart . . .run and see if the noise disappears .
:::
:::
:::ZUJ'ing and waiting to see what your actual findings were . . . .
:::
:::
:::
:::
:::
:::
:::
:::
:::73's de Edd
:::
:::
:::
:::
:::
:::
:::
:::
::::I'm back again. Radio side sounds awsome. Little to ZERO hum. Had the Shure Crystal P90S Phono cartridge rebuilt by westech services and put it in. Phono is there but hums too much with respect to audio.. what are the suspect things to get rid of it or are they all this bad? I did all the filter caps a few years back maybee 6 years ago..
::::
::::Bubba
::::
:::
:::
::
::
:
:
I wonder,, the phono sounds great now but is there anything I can do to decrease the volume? The thing blares on the lowest volume setting. I guess Westech really did their job well rebuilding that carridge.. I would like to be able to turn the pot up a little more so the wiper is further along as it makes poor connnection at the start or connection and also to have a little more room down low to play it quieter.
Can I shunt the phono signal a little? any tricks?? Preferably without having to take out that dang chassis.
THX
Bubbs
:Congratulations Bubba. I commend you for sticking to the repair of your Philco. You never gave up on it. I would think that you should have the feeling of accomplishment. You probably have learned a few things that will help in your next radio repair.
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THX and what value resistor would you try like 10K or somthing?
THX
:The volume control is taped at 500K. There may be a bad spot in that area of the control. You could try adding a resistor in series with the red wire from the phono cartridge to lessen the amount of audio from the cartridge. This would be a kind of work around for a defective volume control.
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