Many thanks,
Jon.
Have you replaced the electrolytic filter caps. They dry out over time and allow hum or in this case buzz.
In addition vibrators require other special caps to eliminate noise. Did you replace the buffer cap? This will be a cap across secondary of your power transformer, .02 mf in your radio. Notice all the .5 mf caps in and around your vibrator box. These are to supress the buzz.
http://www.nostalgiaair.org/PagesByModel/155/M0018155.pdf
Norm
:Just finished recapping this set(no small feat) and after cleaning the vibrator contacts, all I get is a very loud vibrator buzz out of the speaker. No reception, just the buzz that does not change with the volume control. Have rechecked everything I can think of and am coming up blank. Any suggestions?
:Many thanks,
:Jon.
:
: Have you replaced the electrolytic filter caps. They dry out over time and allow hum or in this case buzz.
:
: In addition vibrators require other special caps to eliminate noise. Did you replace the buffer cap? This will be a cap across secondary of your power transformer, .02 mf in your radio. Notice all the .5 mf caps in and around your vibrator box. These are to supress the buzz.
:
:http://www.nostalgiaair.org/PagesByModel/155/M0018155.pdf
:
:Norm
:
Norm,
Thanks for the response, Yes, I have replaced all the caps including the 'lytics. I am going back over it once again and noticed on the top of the vibrator there is a small square metal device on each side that had a wire going in and out. I can't match this up on the schematic and am wondering if it another cap. It looks like it is original to the vibrator.
Thanks,
Jon.
::Just finished recapping this set(no small feat) and after cleaning the vibrator contacts, all I get is a very loud vibrator buzz out of the speaker. No reception, just the buzz that does not change with the volume control. Have rechecked everything I can think of and am coming up blank. Any suggestions?
::Many thanks,
::Jon.
O.K. I will respond in the manner of submitting this thumbnail for you to consult and then sequentially evaluate your units power supply and then move on through its audio stages.
Initially check your battery supply source with the unit "buzzing", thus confirming that the unit is maintaining its primary power source without its being pulled down any by loading effect. And also
hopefully, your vibrator contacts concentricity of contact action will be in sync enough to optimally
switch to produce adequate B+ on the transformer secondary.
Next, refer to red boxed items 1-2-3 and refer back to us the DC voltages taken at those points..... with
chasssis ground being your negative metering reference point.
Considering you have B+ present, and of adequate level, you could then step forward to make a blanket analysis of the speaker and the audio stages .
Now,considering that you might not even have an audio generator....an .01 ufd cap and test leads clipped onto each of the caps leads will suffice.
Now refer down to the blue mark up area and note the possibility of acquiring a signal from either
of the marked up circles on the vibrator / power transformer wiring. This will then permit the extraction of a rich source of vibrator "hash".....otherwise totally undesirable.....and let it suffice for an audio test source.
Take one free lead that is clipped onto the cap and then decide upon either of the blue line marked sources to the vibrator and connect onto it.
Then use the free ended lead ......attached to the caps other lead.... to go up to green box referenced A .
Power up the set and expect the audio to be buzzin' like a bee from the speaker, but not particularly loud at all. Then move the clip to B and expect the same level. Next move the clip lead up to up to point C where there should be some volume increase due to then having a full stage of amplification at this point.
The last test point would involve moving the test lead over to D where all of the audio circuitry in the set would be in circuit and the volume should be at its max.
Standing by for B+ readings ........and to see if one now moves on to evaluate the RF stages, since this would indicate some finite degree of operation of the B+ circuitry along with the audio circuitry. Up to this point you were confirming none of that, merely that the vibrator was buzzing.
73's de Edd
::Jon
::
:: Have you replaced the electrolytic filter caps. They dry out over time and allow hum or in this case buzz.
::
:: In addition vibrators require other special caps to eliminate noise. Did you replace the buffer cap? This will be a cap across secondary of your power transformer, .02 mf in your radio. Notice all the .5 mf caps in and around your vibrator box. These are to supress the buzz.
::
::http://www.nostalgiaair.org/PagesByModel/155/M0018155.pdf
::
::Norm
::
: Norm,
:Thanks for the response, Yes, I have replaced all the caps including the 'lytics. I am going back over it once again and noticed on the top of the vibrator there is a small square metal device on each side that had a wire going in and out. I can't match this up on the schematic and am wondering if it another cap. It looks like it is original to the vibrator.
:Thanks,
:Jon.
:
:
:::Just finished recapping this set(no small feat) and after cleaning the vibrator contacts, all I get is a very loud vibrator buzz out of the speaker. No reception, just the buzz that does not change with the volume control. Have rechecked everything I can think of and am coming up blank. Any suggestions?
:::Many thanks,
:::Jon.
:
:
:
:O.K. I will respond in the manner of submitting this thumbnail for you to consult and then sequentially evaluate your units power supply and then move on through its audio stages.
:
:
:
:Initially check your battery supply source with the unit "buzzing", thus confirming that the unit is maintaining its primary power source without its being pulled down any by loading effect. And also
:hopefully, your vibrator contacts concentricity of contact action will be in sync enough to optimally
:switch to produce adequate B+ on the transformer secondary.
:
:
:Next, refer to red boxed items 1-2-3 and refer back to us the DC voltages taken at those points..... with
:chasssis ground being your negative metering reference point.
:
:Considering you have B+ present, and of adequate level, you could then step forward to make a blanket analysis of the speaker and the audio stages .
:
:
:
:Now,considering that you might not even have an audio generator....an .01 ufd cap and test leads clipped onto each of the caps leads will suffice.
:
:Now refer down to the blue mark up area and note the possibility of acquiring a signal from either
:of the marked up circles on the vibrator / power transformer wiring. This will then permit the extraction of a rich source of vibrator "hash".....otherwise totally undesirable.....and let it suffice for an audio test source.
:Take one free lead that is clipped onto the cap and then decide upon either of the blue line marked sources to the vibrator and connect onto it.
:
:Then use the free ended lead ......attached to the caps other lead.... to go up to green box referenced A .
:Power up the set and expect the audio to be buzzin' like a bee from the speaker, but not particularly loud at all. Then move the clip to B and expect the same level. Next move the clip lead up to up to point C where there should be some volume increase due to then having a full stage of amplification at this point.
:
:The last test point would involve moving the test lead over to D where all of the audio circuitry in the set would be in circuit and the volume should be at its max.
:
:
:Standing by for B+ readings ........and to see if one now moves on to evaluate the RF stages, since this would indicate some finite degree of operation of the B+ circuitry along with the audio circuitry. Up to this point you were confirming none of that, merely that the vibrator was buzzing.
:
:
:
:
:
:
:73's de Edd
:
:
:
Edd,
Many thanks for your advice, I will try them. I tried two power sources, Heathkit BE-4 and an EICO 1064, both operated properly with two other Zenith 6 volts.I will let you all know what I come up with.
Jon.
:
:
:
:
:
:
:
:
:::Jon
:::
::: Have you replaced the electrolytic filter caps. They dry out over time and allow hum or in this case buzz.
:::
::: In addition vibrators require other special caps to eliminate noise. Did you replace the buffer cap? This will be a cap across secondary of your power transformer, .02 mf in your radio. Notice all the .5 mf caps in and around your vibrator box. These are to supress the buzz.
:::
:::http://www.nostalgiaair.org/PagesByModel/155/M0018155.pdf
:::
:::Norm
:::
:: Norm,
::Thanks for the response, Yes, I have replaced all the caps including the 'lytics. I am going back over it once again and noticed on the top of the vibrator there is a small square metal device on each side that had a wire going in and out. I can't match this up on the schematic and am wondering if it another cap. It looks like it is original to the vibrator.
::Thanks,
::Jon.
::
::
::::Just finished recapping this set(no small feat) and after cleaning the vibrator contacts, all I get is a very loud vibrator buzz out of the speaker. No reception, just the buzz that does not change with the volume control. Have rechecked everything I can think of and am coming up blank. Any suggestions?
::::Many thanks,
::::Jon.
Small metal device with wires going through is most likely a fed through cap. It will have capacity from the wire to chassis. Part of the vibrator filter network.
It can be hard filtering all vibrator noise. Might have to try caps while watching the noise on a scope?
Norm
::Jon
::
:: Have you replaced the electrolytic filter caps. They dry out over time and allow hum or in this case buzz.
::
:: In addition vibrators require other special caps to eliminate noise. Did you replace the buffer cap? This will be a cap across secondary of your power transformer, .02 mf in your radio. Notice all the .5 mf caps in and around your vibrator box. These are to supress the buzz.
::
::http://www.nostalgiaair.org/PagesByModel/155/M0018155.pdf
::
::Norm
::
: Norm,
:Thanks for the response, Yes, I have replaced all the caps including the 'lytics. I am going back over it once again and noticed on the top of the vibrator there is a small square metal device on each side that had a wire going in and out. I can't match this up on the schematic and am wondering if it another cap. It looks like it is original to the vibrator.
:Thanks,
:Jon.
:
:
:::Just finished recapping this set(no small feat) and after cleaning the vibrator contacts, all I get is a very loud vibrator buzz out of the speaker. No reception, just the buzz that does not change with the volume control. Have rechecked everything I can think of and am coming up blank. Any suggestions?
:::Many thanks,
:::Jon.
:
: Small metal device with wires going through is most likely a fed through cap. It will have capacity from the wire to chassis. Part of the vibrator filter network.
:
: It can be hard filtering all vibrator noise. Might have to try caps while watching the noise on a scope?
:
:Norm
Norm,
Thanks for the info, unfortunatly using a scope is beyond mt ability at this point. What are the values of the fed through caps and/or are they worth replacing?
Jon.
:
:::Jon
:::
::: Have you replaced the electrolytic filter caps. They dry out over time and allow hum or in this case buzz.
:::
::: In addition vibrators require other special caps to eliminate noise. Did you replace the buffer cap? This will be a cap across secondary of your power transformer, .02 mf in your radio. Notice all the .5 mf caps in and around your vibrator box. These are to supress the buzz.
:::
:::http://www.nostalgiaair.org/PagesByModel/155/M0018155.pdf
:::
:::Norm
:::
:: Norm,
::Thanks for the response, Yes, I have replaced all the caps including the 'lytics. I am going back over it once again and noticed on the top of the vibrator there is a small square metal device on each side that had a wire going in and out. I can't match this up on the schematic and am wondering if it another cap. It looks like it is original to the vibrator.
::Thanks,
::Jon.
::
::
::::Just finished recapping this set(no small feat) and after cleaning the vibrator contacts, all I get is a very loud vibrator buzz out of the speaker. No reception, just the buzz that does not change with the volume control. Have rechecked everything I can think of and am coming up blank. Any suggestions?
::::Many thanks,
::::Jon.
Depends where the caps are located. If they are on primary of the vibrator circuit your radio uses .5 mf.
Norm
::Jon
::
:: Small metal device with wires going through is most likely a fed through cap. It will have capacity from the wire to chassis. Part of the vibrator filter network.
::
:: It can be hard filtering all vibrator noise. Might have to try caps while watching the noise on a scope?
::
::Norm
:Norm,
:Thanks for the info, unfortunatly using a scope is beyond mt ability at this point. What are the values of the fed through caps and/or are they worth replacing?
:Jon.
::
::::Jon
::::
:::: Have you replaced the electrolytic filter caps. They dry out over time and allow hum or in this case buzz.
::::
:::: In addition vibrators require other special caps to eliminate noise. Did you replace the buffer cap? This will be a cap across secondary of your power transformer, .02 mf in your radio. Notice all the .5 mf caps in and around your vibrator box. These are to supress the buzz.
::::
::::http://www.nostalgiaair.org/PagesByModel/155/M0018155.pdf
::::
::::Norm
::::
::: Norm,
:::Thanks for the response, Yes, I have replaced all the caps including the 'lytics. I am going back over it once again and noticed on the top of the vibrator there is a small square metal device on each side that had a wire going in and out. I can't match this up on the schematic and am wondering if it another cap. It looks like it is original to the vibrator.
:::Thanks,
:::Jon.
:::
:::
:::::Just finished recapping this set(no small feat) and after cleaning the vibrator contacts, all I get is a very loud vibrator buzz out of the speaker. No reception, just the buzz that does not change with the volume control. Have rechecked everything I can think of and am coming up blank. Any suggestions?
:::::Many thanks,
:::::Jon.