I am pretty convinced it is either the output tube or the power supply but it is not a hum. I re-soldered all the pins on the weekend and same thing the next day. Of course it did not do it when I had the chassis out (%$*$). Any tips on further isolating this. Can I put off certain pins to see where it is coming from on the EL84? Could it be the Tube Socket??
Doesn't really happen more or less when I wiggle the tube. Nor when I poke around with a chop stick. Very annoying it is like somthing is not making solid connection or like a cold solder joint..
Only thing I noticed that is remotly strange is when I take a voltage measurment on one of the lugs of the elecrolytic it kind of arcs. Is this normal? The Cap is a multi lug replacment and is not that old. Other than that all the voltages are pretty normal. Could it be a cap on the EL84?
THX
:
:I am pretty convinced it is either the output tube or the power supply but it is not a hum. I re-soldered all the pins on the weekend and same thing the next day. Of course it did not do it when I had the chassis out (%$*$). Any tips on further isolating this. Can I put off certain pins to see where it is coming from on the EL84? Could it be the Tube Socket??
:
: Doesn't really happen more or less when I wiggle the tube. Nor when I poke around with a chop stick. Very annoying it is like somthing is not making solid connection or like a cold solder joint..
:
:Only thing I noticed that is remotly strange is when I take a voltage measurment on one of the lugs of the elecrolytic it kind of arcs. Is this normal? The Cap is a multi lug replacment and is not that old. Other than that all the voltages are pretty normal. Could it be a cap on the EL84?
:
:THX
:
You may want to check and clean all band switches, volume controls and tone controls.
These can all be sources of noise, static or intermittnant operation.
Application of contact cleaner while rotating controls or operating switches is the prescribed method.
::
::I am pretty convinced it is either the output tube or the power supply but it is not a hum. I re-soldered all the pins on the weekend and same thing the next day. Of course it did not do it when I had the chassis out (%$*$). Any tips on further isolating this. Can I put off certain pins to see where it is coming from on the EL84? Could it be the Tube Socket??
::
:: Doesn't really happen more or less when I wiggle the tube. Nor when I poke around with a chop stick. Very annoying it is like somthing is not making solid connection or like a cold solder joint..
::
::Only thing I noticed that is remotly strange is when I take a voltage measurment on one of the lugs of the elecrolytic it kind of arcs. Is this normal? The Cap is a multi lug replacment and is not that old. Other than that all the voltages are pretty normal. Could it be a cap on the EL84?
::
::THX
::
:
:You may want to check and clean all band switches, volume controls and tone controls.
:These can all be sources of noise, static or intermittnant operation.
:Application of contact cleaner while rotating controls or operating switches is the prescribed method.
:Could it be the electostatic speakers? The foam in them dries out and they can make unwanted noise and popping. Also agree switches are trouble area and hard to get cleaned up.
Paul
Also check any resistors associated with this tube, and finally check the tube itself for element-to-element shorts, if possible.
Capacitor arcing can only be duplicated with duplicate voltages. If a good high voltage capacitor analyzer is not available, measure grid and plate voltages with a good sensitive meter, and watch for jumping.
Depending on the age, most German radios use metalized film capacitors, which are highly reliable, but some do not, and some use a mix. In any case, check all capacitors to be sure.
Regarding electrolytics, if you are connecting and disconnecting an electrolytic from a fairly high voltage source, there can be slight arcing or sparking because electrolytics posses leakage and drain down a bit when voltage is removed. If the electrolytics in your radio, even being replacements, haven't been used in a while, they may need a little reforming. New well formed electrolytics typically don't spark much once initially charged, but sometimes do. Also, don't rule out internal arcing of the electrolytics as a source of crackling, though if they appear to be fairly new, and it has been determined that they are not the cause of static, you can most likely put them to good use.
T.
Would it hurt to pull pin 2 (Grid) off of the EL 84 and let it run/listen to it? This would prove whether or not static was from that Audio Cap you mention or pots or anything else in the audio chain at all wouldn't it? THen if it still happens I can look at the alternatives..
I just don't want to hurt anything by doing this. This morning the static was barely any. It flares up and then dissapears. Drives my crazy..
:I would suspect the DC blocking/audio bypass capacitor that feeds the grid of the output tube, or any tone capacitors associated with this circuit or the plate circuit of the output tube. Leakage and/or arcing of the grid capacitor would feed B+ from the preceding stage into the grid of the output tube. Arcing tone capacitors would be evident if in this section of the circuitry or in the plate circuit of the output tube.
:
:Also check any resistors associated with this tube, and finally check the tube itself for element-to-element shorts, if possible.
:
:Capacitor arcing can only be duplicated with duplicate voltages. If a good high voltage capacitor analyzer is not available, measure grid and plate voltages with a good sensitive meter, and watch for jumping.
:
:Depending on the age, most German radios use metalized film capacitors, which are highly reliable, but some do not, and some use a mix. In any case, check all capacitors to be sure.
:
:Regarding electrolytics, if you are connecting and disconnecting an electrolytic from a fairly high voltage source, there can be slight arcing or sparking because electrolytics posses leakage and drain down a bit when voltage is removed. If the electrolytics in your radio, even being replacements, haven't been used in a while, they may need a little reforming. New well formed electrolytics typically don't spark much once initially charged, but sometimes do. Also, don't rule out internal arcing of the electrolytics as a source of crackling, though if they appear to be fairly new, and it has been determined that they are not the cause of static, you can most likely put them to good use.
:
:T.
:
Arcing in capacitors can be sporadic. In most cases it has been for me. With some sets I can turn them off and back on and have it go away for a while. In others it is completely random.
Rapid voltage fluctuation, best indicated by a very sensitive meter, such as a VTVM or digital meter, though a 100,000 ohm per volt meter will do, can also indicate arcing.
If you disconnect all capacitors from the output tube and the problem still doesn't go away, check resistors and also the electrolytics by substitution. If the tube sockets are phenolic wafer, don't rule them out. Check contacts for looseness and corrosion. Coat tube pins with dielectric grease if necessary.
If all else fails, look for arcing in a darkened room.
T.
I remember your initial encountrs with that unit back at the last of 2010. |
:I agree. Also try disconnecting any tone capacitor at the plate.
:
:Arcing in capacitors can be sporadic. In most cases it has been for me. With some sets I can turn them off and back on and have it go away for a while. In others it is completely random.
:
:Rapid voltage fluctuation, best indicated by a very sensitive meter, such as a VTVM or digital meter, though a 100,000 ohm per volt meter will do, can also indicate arcing.
:
:If you disconnect all capacitors from the output tube and the problem still doesn't go away, check resistors and also the electrolytics by substitution. If the tube sockets are phenolic wafer, don't rule them out. Check contacts for looseness and corrosion. Coat tube pins with dielectric grease if necessary.
:
:If all else fails, look for arcing in a darkened room.
:
:T.
:
:I agree. Also try disconnecting any tone capacitor at the plate.
:
:Arcing in capacitors can be sporadic. In most cases it has been for me. With some sets I can turn them off and back on and have it go away for a while. In others it is completely random.
:
:Rapid voltage fluctuation, best indicated by a very sensitive meter, such as a VTVM or digital meter, though a 100,000 ohm per volt meter will do, can also indicate arcing.
:
:If you disconnect all capacitors from the output tube and the problem still doesn't go away, check resistors and also the electrolytics by substitution. If the tube sockets are phenolic wafer, don't rule them out. Check contacts for looseness and corrosion. Coat tube pins with dielectric grease if necessary.
:
:If all else fails, look for arcing in a darkened room.
:
:T.
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Well No Luck..
Shorting out the AF it is still there.
It is not the Electro Static Speaker.
It is not the Filter Caps Swapped em..
It is not the cap that feeds the grid of the EL84.
It is not the output tube, Swapped it.
swapped the Cathode bypass Cap for the EL84
It does happen on Phono.
It does Happen on AM and FM and MW
I think it is in the output. But where? Should I replace that 1.3K 3W wirewound?
All resistors measure what they should..
Crack Sizzle Pop UGH!... No damn luck.
:Actually a while back I did notice a fluctuating cathode voltage up then down. My radio was getting really loud. But then I swapped EL84 with another and it was fine I don't thinkt he tube was back though. I better check all caps in the output. The caps are not the originals. I replaced em a while back. But the one between the EL84 and the tube before it is the one you guys are talking about I will replace it.
:
:
:
::I agree. Also try disconnecting any tone capacitor at the plate.
::
::Arcing in capacitors can be sporadic. In most cases it has been for me. With some sets I can turn them off and back on and have it go away for a while. In others it is completely random.
::
::Rapid voltage fluctuation, best indicated by a very sensitive meter, such as a VTVM or digital meter, though a 100,000 ohm per volt meter will do, can also indicate arcing.
::
::If you disconnect all capacitors from the output tube and the problem still doesn't go away, check resistors and also the electrolytics by substitution. If the tube sockets are phenolic wafer, don't rule them out. Check contacts for looseness and corrosion. Coat tube pins with dielectric grease if necessary.
::
::If all else fails, look for arcing in a darkened room.
::
::T.
::
:
:
Furthermore check the output transformer.
If possible, without excessively increasing B+ to the output stage, try disconnecting the rest of the radio--B+ to all other stages, and, of course, the input to the grid of the output tube. -DISCONNECT- the grid capacitor. Don't short it. Remove everything from the output except the power supply, if this is possible. In some radios this can increase B+ excessively, but not necessarily.
If the static is still present, then it definitely lies either in the output section (most likely), or in the power supply.
Good luck.
T.
:Had one Grungid with a leaky audio output transformer. Did not show anything wrong tested with Ohm meter. Subbed in a separate transformer with PM speaker. Hissing crackle problem was gone.
:
Tough ones like that are bothersome, but we learn a bit more. Long before there was much internet and this site, I first learned about silver mica capacitor shorting in 1950s IF transformers, and it was a painful search through a radio that would sometimes run fine and then just cut out. ...And then there was learning about leakage in paper capacitors, since every antique radio repair book at the time said to parallel an old capacitor with a new one to see if it is open, never considering that capacitors rarely open, and very very often start to leak, or sometimes arc, and this is not easily detected with an ordinary ohmmeter.
If you lack things like the high voltage leakage test in, say, a Solar capacitor analyzer, or an insulation tester made by, say, Fluke (prohibitively expensive), you can rig up your own by making a simple AC/DC rectifier-power supply set-up using a suitably rated diode from Radio Shack, and then a filter capacitor or two (new). Rig up whatever it is to be tested using a resistor from 10,000 ohms to 100,000 ohms. Look for voltages where they shouldn't be, or simply wire your voltmeter in series in place of the resistance. For instance, wire a capacitor in series with your voltmeter and look for steady or fluctuating voltage, which would indicate leakage or arcing. With an output transformer, apply the positive of the power supply to the transformer primary. Connect the negative to the negative lead of your meter. Use the positive lead of your meter to probe, say, the secondary coil, or the frame, and look for arcing and/or leakage.
Of course this tester will only test for arcing at about 150 volts or lower, being operated directly from line voltage, but is helpful in many cases. For higher voltages you will need a small step-up transformer.
In all cases be careful not to shock yourself, and if using the AC/DC type supply, remember that it's connected directly to the line supply, and so there is even more shock danger, even if you only touch one wire, so don't touch any of the wires.
T.
:Pulling all of the other tubes still doesn't isolate things like IF transformers, but now, when you electrically isolate the output stage, that should reveal the trouble. Just make sure that the B voltage doesn't climb beyond the rating of the output tube with everything else disconnected.
:
:Tough ones like that are bothersome, but we learn a bit more. Long before there was much internet and this site, I first learned about silver mica capacitor shorting in 1950s IF transformers, and it was a painful search through a radio that would sometimes run fine and then just cut out. ...And then there was learning about leakage in paper capacitors, since every antique radio repair book at the time said to parallel an old capacitor with a new one to see if it is open, never considering that capacitors rarely open, and very very often start to leak, or sometimes arc, and this is not easily detected with an ordinary ohmmeter.
:
:If you lack things like the high voltage leakage test in, say, a Solar capacitor analyzer, or an insulation tester made by, say, Fluke (prohibitively expensive), you can rig up your own by making a simple AC/DC rectifier-power supply set-up using a suitably rated diode from Radio Shack, and then a filter capacitor or two (new). Rig up whatever it is to be tested using a resistor from 10,000 ohms to 100,000 ohms. Look for voltages where they shouldn't be, or simply wire your voltmeter in series in place of the resistance. For instance, wire a capacitor in series with your voltmeter and look for steady or fluctuating voltage, which would indicate leakage or arcing. With an output transformer, apply the positive of the power supply to the transformer primary. Connect the negative to the negative lead of your meter. Use the positive lead of your meter to probe, say, the secondary coil, or the frame, and look for arcing and/or leakage.
:
:Of course this tester will only test for arcing at about 150 volts or lower, being operated directly from line voltage, but is helpful in many cases. For higher voltages you will need a small step-up transformer.
:
:In all cases be careful not to shock yourself, and if using the AC/DC type supply, remember that it's connected directly to the line supply, and so there is even more shock danger, even if you only touch one wire, so don't touch any of the wires.
:
:T.
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Just one Cap.. I think I can swing it.
:Inside that box where all the tuning stuff is. That is all tuned for each radio from the factory. The wax is to hold the components in place so they work as a tuned circuit. Put every thing back where is was originally.
:
I still am no closer to solving the faint crispies being gone though. Replaced 1.3K 3W and the cathode 5W resistor in the output and no dice. I also blew it out with compressed air in the switches and pots etc.
I will begin pulling the HV of, one stage at a time to try and find a stage where it stops.. I really hope it's not the OP transformer how in the hell would I find another... I may as well put one B+ stage back at a time and put back on as I go... Therefore no worry about high voltage creeping up on the output section..
:Those metalized film caps almost never fail. It's almost not worth it to test them.
:
I have noticed also somtimes with the volume all the way down when listening to it quietly at night for example,, it seems like the volume gets slightly louder when tuned into a perticular station. Then when I move the tuner away from the station and then back again, the volume goes back down to normal. Could it be somthing with the tuner?
:It's all good, it was my flatscreen,,, off but plugged in that I was working beside causing the oscillating noise. I thought it was somthing I did. when I pulled the plug on the Flatscreen it was gone. The 330pF is fine where it is in the tuning stage and working.
:
:I still am no closer to solving the faint crispies being gone though. Replaced 1.3K 3W and the cathode 5W resistor in the output and no dice. I also blew it out with compressed air in the switches and pots etc.
:
:I will begin pulling the HV of, one stage at a time to try and find a stage where it stops.. I really hope it's not the OP transformer how in the hell would I find another... I may as well put one B+ stage back at a time and put back on as I go... Therefore no worry about high voltage creeping up on the output section..
:
:
:
:
::Those metalized film caps almost never fail. It's almost not worth it to test them.
::
:
:
However, this still doesn't solve the problem of hearing crispies when all audio to the output stage is disconnected, as a dirty volume control would almost certainly not be heard if the capacitor to the output grid were disconnected.
If you are hearing crispies with the 1st audio stage disconnected, then the problem lies either in the output section or the B+ rail or the power supply.
I have one 35L6 that makes slight crispy noises. It just happens with that tube, and all solder connections are fine, and there are no measurable shorts. ..Not sure why it does it. However, you say that you swapped output tubes at least once, and the problem remained.
T.
:Could be, or could be something with the volume control. Is it otherwise smooth in operation? Sometimes a strong input signal can upset a dirty volume control.
:
:However, this still doesn't solve the problem of hearing crispies when all audio to the output stage is disconnected, as a dirty volume control would almost certainly not be heard if the capacitor to the output grid were disconnected.
:
:If you are hearing crispies with the 1st audio stage disconnected, then the problem lies either in the output section or the B+ rail or the power supply.
:
:I have one 35L6 that makes slight crispy noises. It just happens with that tube, and all solder connections are fine, and there are no measurable shorts. ..Not sure why it does it. However, you say that you swapped output tubes at least once, and the problem remained.
:
:T.
:
:I am beginning to lose faith in fixing this. As far as I know it seems to happen no matter what I do. Maybe I shoud change the output tube socket. How do you tell if it is the transformer windings arcking It seems like before it starts happening I hear a mild pop Then the scratchiness.. It is like a bad connection or wires making contact trhough insulation intermittantly. Anyone else got an idea? I have practically replace every cap in the output. Resistor measure proper values and voltages seem right.
:
:
:
:
:
::Could be, or could be something with the volume control. Is it otherwise smooth in operation? Sometimes a strong input signal can upset a dirty volume control.
::
::However, this still doesn't solve the problem of hearing crispies when all audio to the output stage is disconnected, as a dirty volume control would almost certainly not be heard if the capacitor to the output grid were disconnected.
::
::If you are hearing crispies with the 1st audio stage disconnected, then the problem lies either in the output section or the B+ rail or the power supply.
::
::I have one 35L6 that makes slight crispy noises. It just happens with that tube, and all solder connections are fine, and there are no measurable shorts. ..Not sure why it does it. However, you say that you swapped output tubes at least once, and the problem remained.
::
::T.
::
:
:
:It coudn't be MY wall 120 AC or outside interference could it? It does sound internal to the radio IMO.
:
:
:
:
::I am beginning to lose faith in fixing this. As far as I know it seems to happen no matter what I do. Maybe I shoud change the output tube socket. How do you tell if it is the transformer windings arcking It seems like before it starts happening I hear a mild pop Then the scratchiness.. It is like a bad connection or wires making contact trhough insulation intermittantly. Anyone else got an idea? I have practically replace every cap in the output. Resistor measure proper values and voltages seem right.
::
::
::
::
::
:::Could be, or could be something with the volume control. Is it otherwise smooth in operation? Sometimes a strong input signal can upset a dirty volume control.
:::
:::However, this still doesn't solve the problem of hearing crispies when all audio to the output stage is disconnected, as a dirty volume control would almost certainly not be heard if the capacitor to the output grid were disconnected.
:::
:::If you are hearing crispies with the 1st audio stage disconnected, then the problem lies either in the output section or the B+ rail or the power supply.
:::
:::I have one 35L6 that makes slight crispy noises. It just happens with that tube, and all solder connections are fine, and there are no measurable shorts. ..Not sure why it does it. However, you say that you swapped output tubes at least once, and the problem remained.
:::
:::T.
:::
::
::
:
:
In the schem A+ is 275 and Pin 7 is supposed to be 260 and Pin 9 is 210 which I got 209. My point is the voltages are alot more ball park with the 125 Tap and lower and I wonder if I had noticed that I was eating output tubes quite quickly. Could it be that my voltages were simply too high? I would think I am on the right tap now as I read exactly 6.3 AC on the filaments on this tap. I put in a 3rd output tube and I do not here any crackling. I wonder if I was frying them which would explain the need to keep swapping them out once a year.
:Could try disconnecting the primary side of the audio output transformer. Sub in another transformer from any AA5. Connect primary to filtered B+ and to plate of output tube.
:
THANX to all.
:I have an annoying faint scratching in the single ended EL84 Output of my Grundig 1088. It get's louder and softer by itself. I have removed all tubes except the Power tube and I still hear it on AM and FM and also Phono.
:
:I am pretty convinced it is either the output tube or the power supply but it is not a hum. I re-soldered all the pins on the weekend and same thing the next day. Of course it did not do it when I had the chassis out (%$*$). Any tips on further isolating this. Can I put off certain pins to see where it is coming from on the EL84? Could it be the Tube Socket??
:
: Doesn't really happen more or less when I wiggle the tube. Nor when I poke around with a chop stick. Very annoying it is like somthing is not making solid connection or like a cold solder joint..
:
:Only thing I noticed that is remotly strange is when I take a voltage measurment on one of the lugs of the elecrolytic it kind of arcs. Is this normal? The Cap is a multi lug replacment and is not that old. Other than that all the voltages are pretty normal. Could it be a cap on the EL84?
:
:THX
: