Crosley 655 Polarity for Electrolytics

1/1/2012 10:26:48 AMSteve Larson

I am replacing the electrolytic can and would appreaciate advice on polarity orientation for parts 10z, 10y and 10x. When I obtained the radio the termnals were all disconnected. I am using 3 separate 10 MFD caps.

The transformer and tubes all test OK.

I can upload a copy of the schematic if needed.

Thanks

Steve

1/1/2012 10:55:13 AMTerry Decker

:I am replacing the electrolytic can and would appreaciate advice on polarity orientation for parts 10z, 10y and 10x. When I obtained the radio the termnals were all disconnected. I am using 3 separate 10 MFD caps.
:
:The transformer and tubes all test OK.
:
:I can upload a copy of the schematic if needed.
:
:Thanks

The negative pole usually goes to system ground which may, or may not be the chassis. Generally the ground is the cap itself, such as the tabs holding the tab to the chassis. If there is solder on any of those tabs, that is where the minus goes. If not then look for the ground which should be indicated on the schematic.
Terry
:
:Steve
:
:
:

1/1/2012 12:16:10 PMWarren

Capacitor 10X positive side connects to junction of resistors 41Y and 41Z. Capacitor 10Y positive side connects to cathode of 5Z4. both 10X and 10Y share the same negative ground point. Capacitor 10Z positive side also connects to cathode of 5Z4. Negative side to transformer center tap.

1/1/2012 12:19:51 PMBill G.

Hi Steve,
The schematic is here. For 10Z and 10Y the positive connects to the tube, 5Z4. For 10X, the positive connects to the two resistors.
That is all there is to it!

Best Regards,

Bill Grimm

1/1/2012 1:23:17 PMSteve Larson

Thanks,

I made the connections but do not read any voltage on the plates for any tube except the 5Z4.

There must be somethinh else wrong with the wiring.

Any ideas?

Steve

:Hi Steve,
: The schematic is here. For 10Z and 10Y the positive connects to the tube, 5Z4. For 10X, the positive connects to the two resistors.
: That is all there is to it!
:
:Best Regards,
:
:Bill Grimm
:

1/1/2012 3:00:37 PMWarren

The main B+ comes off the cathode ( filament ) of the 5Z4. marked as K. If you follow this wire it goes though the field coil then to the plate of the 6F6. The voltage from the cathode of the 5Z4 is also the source for all B+ ( Note ) the most negative ground is the center tap of the transformer. This is where your negative test probe would go to test the raw B+. The rest of the voltages would be read from the B- ground. ( the thick black line though the middle of the schematic. )

1/1/2012 4:02:26 PMBill G.

Hi Steve,
Warren is giving you good advice. Mine is only an add on to his.
Often the resistors that form the votage divider to bias the power output tube (6F6 in this case) get corroded. This kills all the plate voltages. These resistors in this Crosley are labeled 30, 34 and 36B.
If checking with an ohm meter (power off) they read significantly high or open, that is your problem.

Good luck in trouble shooting,

Bill Grimm

1/1/2012 5:48:08 PMTerry Decker

:Thanks,
:
:I made the connections but do not read any voltage on the plates for any tube except the 5Z4.
:
:There must be somethinh else wrong with the wiring.
:
:Any ideas?
:
:
:Steve

I assume you've checked the field coil.
t.
:
:
::Hi Steve,
:: The schematic is here. For 10Z and 10Y the positive connects to the tube, 5Z4. For 10X, the positive connects to the two resistors.
:: That is all there is to it!
::
::Best Regards,
::
::Bill Grimm
::
:
:

1/2/2012 11:05:12 AMTerry Decker

:Thanks,
:
:I made the connections but do not read any voltage on the plates for any tube except the 5Z4.
:
:There must be somethinh else wrong with the wiring.
:
:Any ideas?
:
:
:Steve
:
:
::Hi Steve,
:: The schematic is here. For 10Z and 10Y the positive connects to the tube, 5Z4. For 10X, the positive connects to the two resistors.
:: That is all there is to it!
::
::Best Regards,
::
::Bill Grimm
::
:
:If it does turn out that there is a problem with the field coil and if you haven't already done so- there are a couple of ways to fix that.
Terry

1/8/2012 12:03:28 PMSteve Larson

::Thanks,
::
::I made the connections but do not read any voltage on the plates for any tube except the 5Z4.
::
::There must be somethinh else wrong with the wiring.
::
::Any ideas?
::
::
::Steve
::
::
:::Hi Steve,
::: The schematic is here. For 10Z and 10Y the positive connects to the tube, 5Z4. For 10X, the positive connects to the two resistors.
::: That is all there is to it!
:::
:::Best Regards,
:::
:::Bill Grimm
:::
::
::If it does turn out that there is a problem with the field coil and if you haven't already done so- there are a couple of ways to fix that.
:Terry
:
:
Thanks for yor help.

I now have voltage but the readings are not quite what they should be.

All paper caps and resistors have been replaced, but I do not have sound (other then buzzing). When I hook my signal generator up to the antenna I have only faint sound in the first stage- the others appear to be fine. The occilator coil (Item 7 on the schematic) gives no reading-could that be the problem? Can you suggest a source for replacement?

Also, Capacitors 22Z and 22Y are combined and I am not really clear on how to rewire two separate replacements.

Any suggestions would be appreciated.

Thanks

Steve Larson

1/8/2012 12:41:33 PMWarren

Capacitors 22Y and 22Z are for tone compensation. Both of the positive ends are joined together, and connect to the plate of the 6F6. 22Y negative end goes to the switched side of the switch. 22Z negative side, goes to the other side of the switch.
Did you read the oscillator coils for continuity ?

1/8/2012 1:24:30 PMSteve Larson

:Capacitors 22Y and 22Z are for tone compensation. Both of the positive ends are joined together, and connect to the plate of the 6F6. 22Y negative end goes to the switched side of the switch. 22Z negative side, goes to the other side of the switch.
:Did you read the oscillator coils for continuity ?
:

Yes,

Items 7 & 8 have continuity; Item 9 does not.

1/8/2012 1:53:29 PMWarren

Item 9 is a shortwave oscillator coil. With the band switch in the AM position this would use the AM oscillator coil item 7. test for negative voltage on pin 5 of the 6A8 while in this position.

1/8/2012 5:12:53 PMSteve Larson

:Item 9 is a shortwave oscillator coil. With the band switch in the AM position this would use the AM oscillator coil item 7. test for negative voltage on pin 5 of the 6A8 while in this position.

Ok : The results were:

With the variable cap fully closed, voltages are as follows: Pin 3 165v, Pin 4 101v, Pin 5 -.01v, Pin 6 165v, Pin 7 0v., Pin 8 2.8v.

With the variable cap fully open, Pin 5 is -7.7v and 1/2 way open, the voltage peaks at -22.5v.

Steve

1/8/2012 6:12:34 PMMitch

::Item 9 is a shortwave oscillator coil. With the band switch in the AM position this would use the AM oscillator coil item 7. test for negative voltage on pin 5 of the 6A8 while in this position.
:
:Ok : The results were:
:
:With the variable cap fully closed, voltages are as follows: Pin 3 165v, Pin 4 101v, Pin 5 -.01v, Pin 6 165v, Pin 7 0v., Pin 8 2.8v.
:
:With the variable cap fully open, Pin 5 is -7.7v and 1/2 way open, the voltage peaks at -22.5v.
:
:Steve
:
:
:
Hello Steve,

There is a tube legend with your schematic. Pin 5 should be a negative DC voltage.

Pin 5 should be between -4 to -10 VDC.

Follow the tube legend for your voltage measurements.

My question is if you are using a VTVM? Sometimes a digital volt meter will give poor readings due to a lack of impedance.

Mitch

1/9/2012 11:35:22 AMEdd

Sir Steve EL L L L L L L . . . . .

Holy Mackeral, 'dere Andy . . . . methinks that 'ole Powell Crosley would roll over in his grave if hearing of one of his receivers not wukkin' properly.

All of your given voltages for the receiver seem in line excepting for that pin 5 oscillator grid . . . when it is being FULLY closed / meshed.

As already mentioned we would be initially interested in the sets band switch being in the AM position and not either of the two other lo or hi SW bands.

Lets at least be "fishing" for any reception where there are the most potential stations and not in a dry mud hole, as the two other SW bands potentially might be.

That will be having the item # 2 antenna coil being used along with its companion item # 7 osc coil.

With that almost ZERO voltage on the 6A8 pin # 5 is suggestive of a rotary plate on the oscillator section of the tuning condenser ( Item 25 W), shorting out to a stationary plate across from it, in that max meshed position where there are the potentially most plates areas involved.

Fully investigate that likely situation .

Soooooooooo, why is there not the OTHER possible potential of a like situation of the separate and companion antenna tuning section ( Item 25 Z), of the capacitor having the SAME situation, thereby accounting for NO antenna signal getting into the radio.

A no reception at all situation.

Note that their companion tuning coils are shunting each section of those tuning condensers, so one would have to temporarily lift those connections to the stationary bank of plates of those respective sections of the tuning condensers TEMPORARILY while ohmically testing for any shorting out of the rotary to stationary plate banks

Naturally, that potential is being the greatest on the max meshed position along with the rotors outer single plates which are most susceptible / accesible to getting bent inwards.

An INITIAL test to check out would be to take the unit and warm up and place in BC band and place the tuning condenser to that just opened position where you are THEN getting pin #5 negative voltage, with that being an indication of local oscillator activity.

Then you will use your 'ole body mass as an impromptu antenna and touch a spit wetted finger to the grid cap atop the 6A8, that will then be getting incoming RF signals into the 6A8 RF input circuitry.

You then be sure that your other hand , that you would be doing the gripping and turning of the tuning condenser shaft . . . . a ground situation . . . is having an insulated knob on that shaft, OR else, you will be sending all of your bodys received RF potential to GROUND, with none getting into that grid cap.

If you are then able to receive any station while tuning across the band, that would be indicative of a problem in that frontal RF / antenna section. But do note that, in this exploratory testing procedure, it is NORMAL for received stations to NOT have clear audio but the taking on of an underwater / blurbling sounds intonation.

Thassit . . . .now see how it goes . . . .

73's de Edd

It was recently discovered that research causes cancer in rats.

:::Item 9 is a shortwave oscillator coil. With the band switch in the AM position this would use the AM oscillator coil item 7. test for negative voltage on pin 5 of the 6A8 while in this position.
::
::Ok : The results were:
::
::With the variable cap fully closed, voltages are as follows: Pin 3 165v, Pin 4 101v, Pin 5 -.01v, Pin 6 165v, Pin 7 0v., Pin 8 2.8v.
::
::With the variable cap fully open, Pin 5 is -7.7v and 1/2 way open, the voltage peaks at -22.5v.
::
::Steve
::
::
::
:Hello Steve,
:
:There is a tube legend with your schematic. Pin 5 should be a negative DC voltage.
:
:Pin 5 should be between -4 to -10 VDC.
:
:Follow the tube legend for your voltage measurements.
:
:My question is if you are using a VTVM? Sometimes a digital volt meter will give poor readings due to a lack of impedance.
:
:Mitch
:

1/11/2012 8:41:27 PMSteve Larson

:Thanks everyone for your comments and suggestions.

They have been a lot of help.

There were multiple issues going on with the set including a faulty resistor assembly, frayed wire shorting out the signal, a missing connecting wire when a previous "mechanic" tried to fix it, etc.

The good news is that the set now plays.

:
:

:
:
:
:
:
:
:
:
:
:
:
:Sir Steve EL L L L L L L . . . . .
:
:
:Holy Mackeral, 'dere Andy . . . . methinks that 'ole Powell Crosley would roll over in his grave if hearing of one of his receivers not wukkin' properly.
:
:
:All of your given voltages for the receiver seem in line excepting for that pin 5 oscillator grid . . . when it is being FULLY closed / meshed.
:
:
:As already mentioned we would be initially interested in the sets band switch being in the AM position and not either of the two other lo or hi SW bands.
:
:
:Lets at least be "fishing" for any reception where there are the most potential stations and not in a dry mud hole, as the two other SW bands potentially might be.
:
:
:That will be having the item # 2 antenna coil being used along with its companion item # 7 osc coil.
:
:
:With that almost ZERO voltage on the 6A8 pin # 5 is suggestive of a rotary plate on the oscillator section of the tuning condenser ( Item 25 W), shorting out to a stationary plate across from it, in that max meshed position where there are the potentially most plates areas involved.
:
:
:Fully investigate that likely situation .
:
:
:Soooooooooo, why is there not the OTHER possible potential of a like situation of the separate and companion antenna tuning section ( Item 25 Z), of the capacitor having the SAME situation, thereby accounting for NO antenna signal getting into the radio.
:
:
:A no reception at all situation.
:
:
:Note that their companion tuning coils are shunting each section of those tuning condensers, so one would have to temporarily lift those connections to the stationary bank of plates of those respective sections of the tuning condensers TEMPORARILY while ohmically testing for any shorting out of the rotary to stationary plate banks
:
:
:Naturally, that potential is being the greatest on the max meshed position along with the rotors outer single plates which are most susceptible / accesible to getting bent inwards.
:
:
:An INITIAL test to check out would be to take the unit and warm up and place in BC band and place the tuning condenser to that just opened position where you are THEN getting pin #5 negative voltage, with that being an indication of local oscillator activity.
:
:
:Then you will use your 'ole body mass as an impromptu antenna and touch a spit wetted finger to the grid cap atop the 6A8, that will then be getting incoming RF signals into the 6A8 RF input circuitry.
:
:
:You then be sure that your other hand , that you would be doing the gripping and turning of the tuning condenser shaft . . . . a ground situation . . . is having an insulated knob on that shaft, OR else, you will be sending all of your bodys received RF potential to GROUND, with none getting into that grid cap.
:
:
:If you are then able to receive any station while tuning across the band, that would be indicative of a problem in that frontal RF / antenna section. But do note that, in this exploratory testing procedure, it is NORMAL for received stations to NOT have clear audio but the taking on of an underwater / blurbling sounds intonation.
:
:
:Thassit . . . .now see how it goes . . . .
:
:
:
:73's de Edd
:
:
:
:
:It was recently discovered that research causes cancer in rats.
:
:
:
:
:
:
:

:
:
:
:
::::Item 9 is a shortwave oscillator coil. With the band switch in the AM position this would use the AM oscillator coil item 7. test for negative voltage on pin 5 of the 6A8 while in this position.
:::
:::Ok : The results were:
:::
:::With the variable cap fully closed, voltages are as follows: Pin 3 165v, Pin 4 101v, Pin 5 -.01v, Pin 6 165v, Pin 7 0v., Pin 8 2.8v.
:::
:::With the variable cap fully open, Pin 5 is -7.7v and 1/2 way open, the voltage peaks at -22.5v.
:::
:::Steve
:::
:::
:::
::Hello Steve,
::
::There is a tube legend with your schematic. Pin 5 should be a negative DC voltage.
::
::Pin 5 should be between -4 to -10 VDC.
::
::Follow the tube legend for your voltage measurements.
::
::My question is if you are using a VTVM? Sometimes a digital volt meter will give poor readings due to a lack of impedance.
::
::Mitch
::
:
: