Someone worked on this radio and left a resistor hanging. So I would like to look at the schematic to figure out what was done. Does anyone have a copy of the schematic I could look at?
Thanks,
Dave
This is the Electrovox Model BX-326. BC-SW 10 Transistor SW radio. It's a large "Pocket" sized radio. It looks like it's from the 60s or 70s.
Do you think there is a chance that it is the same radio ?
I can provide you with the schematic of the Sharp if you like
Yes, that's it. It has a Sharp Speaker in it and looks just like the Sharp BX-321 except it says Electrovox on the front Logo instead of Sharp. But it's the same BC Shortwave set.
Thanks,
Dave
:Sharp produced a model BX-326 (Circa 1964)with 10 transistors.
:
:Do you think there is a chance that it is the same radio ?
:
:I can provide you with the schematic of the Sharp if you like
:
Yes, that's it exactly except for the logo, which says Electrovox instead of Sharp.
I like the look of it and would like to get it working.
Thanks,
Dave
:Here is an image of the Sharp BX-326 for you to compare:
:
:
:
There is no "thump" when I turn it on. Where do I check for it. I can't find anything wrong. But, of course there is.
The speaker works. I get continuity on the audio transformers. Every resistor I check seems to be ok but I'm willing to recheck things. Voltages are present too.
Thanks,
Dave
:Service data sent
:
Now that you have the schematic do you have a signal tracer that you can use to find out where the signal appears or disappears ?
the center tap of the secondary of the driver transformer . . .or . . . |
BX-326 Transistor Radio Schematic Mark-Up:  |
:Now that you have the schematic do you have a signal tracer that you can use to find out where the signal appears or disappears ?
:do you hear anything at all from the speaker.....hiss, static etc ? ...........or is it dead silent ?
:
:
:
I'm getting a 1K resistor from my resistor drawer now. I'll send my results in a few minutes.
Thanks,
Dave
:
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:
:Sir Dave. . . . .
:
:
:Well . . . . in initially perusing over the units design, ( its shematic DOOOOOOWN bee-low) we see no hi value output stage to speaker coupling capacitor in the mix.
:With the unit, instead, using old style transformer to speaker drive.
:
:
:In the lineup of its multi decades old electrolytic capacitors used . . .ref to mark-up . . . CAPS A-B-C-D are power supply filtering / decoupling related and shouldn't knock out the set.
:
:
:Same is true of the E-F’s , which are related to filtering the AVC buss and also should not knock out the set.
:
:
:Electrolytic G up in the TR-7 collector circuitry is tone control function related, but could result in gain loss if being excessively leaky.
:
:
:Electrolytic I, is serving as a partial emitter bypass for TR-6 could account for slight gain drain, along with an accompanying bass decline, if decreased way down in capacitance.
:
:
:AND THEN . . . the major suspects would be AF interstage coupling capacitors H and J, if opened up.
:
:
:Other check points:
:
:
:Confirm if a “sprung open “ headphone jack switching mechanism is not opening up the path of the output transformer to the speaker, as well as ohmically testing the speaker voice coil.
:
:
:
:
:
:Kasper Pee Clodddd, special LOW tech . . . yet highly effective . . . “seat of pants” test procedure:
:
:
:
:
:Take a 1K resistor and clip lead connect one of its leads to this sets main BEE minus . . . . notice I did's say BEE Minus-es-es-es supply, since this set is incorporating a cluster of "upside down and backwards" Pee Enn Pee transisto-mo-fers. .
:
:
:The other lead is then taken and used in a manner like the “quick striking of a match” to any of the multi commonly connected junctions of:
:
: the center tap of the secondary of the driver transformer . . .or . . .
:
:
:Resistor R32. . .or . . .
:
:
:The Thermistor ( for temp comp) . . .or . . .
:
:
:Resistor R31 .
:
:
:Now if Tr-8 and Tr-9 are amplifying, that should result in a like burst of “scratch” noise emanating from the speaker.
:Move forward in the circuitry to Tr-7 transistor and perform the same “scratch test” on its BASE, but expect a much healthier aural response this time.
:
:
:Next test would be to “scratch” the BASE of the Tr-6 transistor stage and expect the loudest response yet.
:
:
:The final checks would be to run up the sets 5K volume control to its max volume position and “scratch “ both its rotor and high side terminal to verify that control, along with their responsive high level aural “scratches” coming from the speaker.
:
:
:That tests sequential completion should confirm the operationality of the audio chain on that unit, if BEE minus supply from the power supply and semiconductors---resistors---capacitors were all being O.K.
:
:
:If set is still inoperative . . .looks like RF is involved . . . will stand by at this time, awaiting your findings feedback.
:
:
:
:
:
:
:73's de Edd
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:
:No time for a bath? . . . Simple . . . . just wrap yourself in masking tape and remove the dirt by simply peeling it off.
:
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: BX-326 Transistor Radio Schematic Mark-Up:
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::do you hear anything at all from the speaker.....hiss, static etc ? ...........or is it dead silent ?
::
:
:
::Now that you have the schematic do you have a signal tracer that you can use to find out where the signal appears or disappears ?
::
::
:
:
The only place I hear any sound through the speaker is if I touch the other end of the 1k ohm resistor to one end of the thermistor. Everywhere else it's dead.
Thanks,
Dave
:
:
:
:
:
:
:
:
:
:
:
:
:
:Sir Dave. . . . .
:
:
:Well . . . . in initially perusing over the units design, ( its shematic DOOOOOOWN bee-low) we see no hi value output stage to speaker coupling capacitor in the mix.
:With the unit, instead, using old style transformer to speaker drive.
:
:
:In the lineup of its multi decades old electrolytic capacitors used . . .ref to mark-up . . . CAPS A-B-C-D are power supply filtering / decoupling related and shouldn't knock out the set.
:
:
:Same is true of the E-F’s , which are related to filtering the AVC buss and also should not knock out the set.
:
:
:Electrolytic G up in the TR-7 collector circuitry is tone control function related, but could result in gain loss if being excessively leaky.
:
:
:Electrolytic I, is serving as a partial emitter bypass for TR-6 could account for slight gain drain, along with an accompanying bass decline, if decreased way down in capacitance.
:
:
:AND THEN . . . the major suspects would be AF interstage coupling capacitors H and J, if opened up.
:
:
:Other check points:
:
:
:Confirm if a “sprung open “ headphone jack switching mechanism is not opening up the path of the output transformer to the speaker, as well as ohmically testing the speaker voice coil.
:
:
:
:
:
:Kasper Pee Clodddd, special LOW tech . . . yet highly effective . . . “seat of pants” test procedure:
:
:
:
:
:Take a 1K resistor and clip lead connect one of its leads to this sets main BEE minus . . . . notice I did's say BEE Minus-es-es-es supply, since this set is incorporating a cluster of "upside down and backwards" Pee Enn Pee transisto-mo-fers. .
:
:
:The other lead is then taken and used in a manner like the “quick striking of a match” to any of the multi commonly connected junctions of:
:
: the center tap of the secondary of the driver transformer . . .or . . .
:
:
:Resistor R32. . .or . . .
:
:
:The Thermistor ( for temp comp) . . .or . . .
:
:
:Resistor R31 .
:
:
:Now if Tr-8 and Tr-9 are amplifying, that should result in a like burst of “scratch” noise emanating from the speaker.
:Move forward in the circuitry to Tr-7 transistor and perform the same “scratch test” on its BASE, but expect a much healthier aural response this time.
:
:
:Next test would be to “scratch” the BASE of the Tr-6 transistor stage and expect the loudest response yet.
:
:
:The final checks would be to run up the sets 5K volume control to its max volume position and “scratch “ both its rotor and high side terminal to verify that control, along with their responsive high level aural “scratches” coming from the speaker.
:
:
:That tests sequential completion should confirm the operationality of the audio chain on that unit, if BEE minus supply from the power supply and semiconductors---resistors---capacitors were all being O.K.
:
:
:If set is still inoperative . . .looks like RF is involved . . . will stand by at this time, awaiting your findings feedback.
:
:
:
:
:
:
:73's de Edd
:
:
:
:
:No time for a bath? . . . Simple . . . . just wrap yourself in masking tape and remove the dirt by simply peeling it off.
:
:
:
:
:
:
:
:
:
:
:
:
:
: BX-326 Transistor Radio Schematic Mark-Up:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
::do you hear anything at all from the speaker.....hiss, static etc ? ...........or is it dead silent ?
::
:
:
::Now that you have the schematic do you have a signal tracer that you can use to find out where the signal appears or disappears ?
::
::
:
:
My EMC 802 tells me that I have audio all the way up to and just past the volume control. So the problem is somewhere in the amplifier connections. Someone must have "repaired" it and gave up when it didn't work. But I'm pretty sure I will get it working with everyone's help here in the forum. It's already about 90% working.
Thanks,
Dave
:
:
:
:
:
:
:
:
:
:
:
:
:
:Sir Dave. . . . .
:
:
:Well . . . . in initially perusing over the units design, ( its shematic DOOOOOOWN bee-low) we see no hi value output stage to speaker coupling capacitor in the mix.
:With the unit, instead, using old style transformer to speaker drive.
:
:
:In the lineup of its multi decades old electrolytic capacitors used . . .ref to mark-up . . . CAPS A-B-C-D are power supply filtering / decoupling related and shouldn't knock out the set.
:
:
:Same is true of the E-F’s , which are related to filtering the AVC buss and also should not knock out the set.
:
:
:Electrolytic G up in the TR-7 collector circuitry is tone control function related, but could result in gain loss if being excessively leaky.
:
:
:Electrolytic I, is serving as a partial emitter bypass for TR-6 could account for slight gain drain, along with an accompanying bass decline, if decreased way down in capacitance.
:
:
:AND THEN . . . the major suspects would be AF interstage coupling capacitors H and J, if opened up.
:
:
:Other check points:
:
:
:Confirm if a “sprung open “ headphone jack switching mechanism is not opening up the path of the output transformer to the speaker, as well as ohmically testing the speaker voice coil.
:
:
:
:
:
:Kasper Pee Clodddd, special LOW tech . . . yet highly effective . . . “seat of pants” test procedure:
:
:
:
:
:Take a 1K resistor and clip lead connect one of its leads to this sets main BEE minus . . . . notice I did's say BEE Minus-es-es-es supply, since this set is incorporating a cluster of "upside down and backwards" Pee Enn Pee transisto-mo-fers. .
:
:
:The other lead is then taken and used in a manner like the “quick striking of a match” to any of the multi commonly connected junctions of:
:
: the center tap of the secondary of the driver transformer . . .or . . .
:
:
:Resistor R32. . .or . . .
:
:
:The Thermistor ( for temp comp) . . .or . . .
:
:
:Resistor R31 .
:
:
:Now if Tr-8 and Tr-9 are amplifying, that should result in a like burst of “scratch” noise emanating from the speaker.
:Move forward in the circuitry to Tr-7 transistor and perform the same “scratch test” on its BASE, but expect a much healthier aural response this time.
:
:
:Next test would be to “scratch” the BASE of the Tr-6 transistor stage and expect the loudest response yet.
:
:
:The final checks would be to run up the sets 5K volume control to its max volume position and “scratch “ both its rotor and high side terminal to verify that control, along with their responsive high level aural “scratches” coming from the speaker.
:
:
:That tests sequential completion should confirm the operationality of the audio chain on that unit, if BEE minus supply from the power supply and semiconductors---resistors---capacitors were all being O.K.
:
:
:If set is still inoperative . . .looks like RF is involved . . . will stand by at this time, awaiting your findings feedback.
:
:
:
:
:
:
:73's de Edd
:
:
:
:
:No time for a bath? . . . Simple . . . . just wrap yourself in masking tape and remove the dirt by simply peeling it off.
:
:
:
:
:
:
:
:
:
:
:
:
:
: BX-326 Transistor Radio Schematic Mark-Up:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
::do you hear anything at all from the speaker.....hiss, static etc ? ...........or is it dead silent ?
::
:
:
::Now that you have the schematic do you have a signal tracer that you can use to find out where the signal appears or disappears ?
::
::
:
:
I guess I'm going to have to take the PC board out and check the other side. I can find nothing wrong, but it doesn't work. I find voltages to be ok. The transformers are not open. All the resistors are the correct value and connected where they are supposed to connect to. But no audio at the output or output stage. There's plenty of audio at the stage before though. As usual, this is getting frustrating. It should work, but it doesn't. Where do I look next?
Thanks,
Dave
:
:
:
:
:
:
:
:
:
:
:
:
:
:Sir Dave. . . . .
:
:
:Well . . . . in initially perusing over the units design, ( its shematic DOOOOOOWN bee-low) we see no hi value output stage to speaker coupling capacitor in the mix.
:With the unit, instead, using old style transformer to speaker drive.
:
:
:In the lineup of its multi decades old electrolytic capacitors used . . .ref to mark-up . . . CAPS A-B-C-D are power supply filtering / decoupling related and shouldn't knock out the set.
:
:
:Same is true of the E-F’s , which are related to filtering the AVC buss and also should not knock out the set.
:
:
:Electrolytic G up in the TR-7 collector circuitry is tone control function related, but could result in gain loss if being excessively leaky.
:
:
:Electrolytic I, is serving as a partial emitter bypass for TR-6 could account for slight gain drain, along with an accompanying bass decline, if decreased way down in capacitance.
:
:
:AND THEN . . . the major suspects would be AF interstage coupling capacitors H and J, if opened up.
:
:
:Other check points:
:
:
:Confirm if a “sprung open “ headphone jack switching mechanism is not opening up the path of the output transformer to the speaker, as well as ohmically testing the speaker voice coil.
:
:
:
:
:
:Kasper Pee Clodddd, special LOW tech . . . yet highly effective . . . “seat of pants” test procedure:
:
:
:
:
:Take a 1K resistor and clip lead connect one of its leads to this sets main BEE minus . . . . notice I did's say BEE Minus-es-es-es supply, since this set is incorporating a cluster of "upside down and backwards" Pee Enn Pee transisto-mo-fers. .
:
:
:The other lead is then taken and used in a manner like the “quick striking of a match” to any of the multi commonly connected junctions of:
:
: the center tap of the secondary of the driver transformer . . .or . . .
:
:
:Resistor R32. . .or . . .
:
:
:The Thermistor ( for temp comp) . . .or . . .
:
:
:Resistor R31 .
:
:
:Now if Tr-8 and Tr-9 are amplifying, that should result in a like burst of “scratch” noise emanating from the speaker.
:Move forward in the circuitry to Tr-7 transistor and perform the same “scratch test” on its BASE, but expect a much healthier aural response this time.
:
:
:Next test would be to “scratch” the BASE of the Tr-6 transistor stage and expect the loudest response yet.
:
:
:The final checks would be to run up the sets 5K volume control to its max volume position and “scratch “ both its rotor and high side terminal to verify that control, along with their responsive high level aural “scratches” coming from the speaker.
:
:
:That tests sequential completion should confirm the operationality of the audio chain on that unit, if BEE minus supply from the power supply and semiconductors---resistors---capacitors were all being O.K.
:
:
:If set is still inoperative . . .looks like RF is involved . . . will stand by at this time, awaiting your findings feedback.
:
:
:
:
:
:
:73's de Edd
:
:
:
:
:No time for a bath? . . . Simple . . . . just wrap yourself in masking tape and remove the dirt by simply peeling it off.
:
:
:
:
:
:
:
:
:
:
:
:
:
: BX-326 Transistor Radio Schematic Mark-Up:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
::do you hear anything at all from the speaker.....hiss, static etc ? ...........or is it dead silent ?
::
:
:
::Now that you have the schematic do you have a signal tracer that you can use to find out where the signal appears or disappears ?
::
::
:
:
I notice that the collector of TR7 is connected to R30, C39 junction even when I disconnect the other end of the primary of TR1. The only way this can happen is if C37 is shorted. The only problem is that I can't find such a capacitor. There's nothing else connected to the collector of TR7 except for the other end of the primary of the input transformer. When I measure the resistance of TR1 when one end is disconnected, it's about 800 ohms. When it's connected into the circuit it goes down to zero ohms because I'm connecting both ends to the same place somehow. Anyway, it seems like some kind of magic trick. I see no way that junction can connect to the collector, when the other end of the primary is disconnected. The connection is impossible.
I have searched the parts layout and cannot find a C37. So what could possibly be going on? The transistor isn't shorted, as far as I can tell. If I disconnect R21 from R20 and it connect to the disconnected end of the primary of the input transformer I do hear some faint sound from the volume control. This bypasses TR6 and TR7, and shows that the output transistors work fine. There's something weird going on with the output from TR7 to the input transformer. It's total mystery to me, since there's no C37 anywhere. How the connection is being made is just weird. I'll keep checking and see if I can find it. This is interesting but frustrating.
Thanks,
Dave
:Edd,
: I guess I'm going to have to take the PC board out and check the other side. I can find nothing wrong, but it doesn't work. I find voltages to be ok. The transformers are not open. All the resistors are the correct value and connected where they are supposed to connect to. But no audio at the output or output stage. There's plenty of audio at the stage before though. As usual, this is getting frustrating. It should work, but it doesn't. Where do I look next?
:
:Thanks,
:
:Dave
::
::
::
::
::
::
::
::
::
::
::
::
::
::Sir Dave. . . . .
::
::
::Well . . . . in initially perusing over the units design, ( its shematic DOOOOOOWN bee-low) we see no hi value output stage to speaker coupling capacitor in the mix.
::With the unit, instead, using old style transformer to speaker drive.
::
::
::In the lineup of its multi decades old electrolytic capacitors used . . .ref to mark-up . . . CAPS A-B-C-D are power supply filtering / decoupling related and shouldn't knock out the set.
::
::
::Same is true of the E-F’s , which are related to filtering the AVC buss and also should not knock out the set.
::
::
::Electrolytic G up in the TR-7 collector circuitry is tone control function related, but could result in gain loss if being excessively leaky.
::
::
::Electrolytic I, is serving as a partial emitter bypass for TR-6 could account for slight gain drain, along with an accompanying bass decline, if decreased way down in capacitance.
::
::
::AND THEN . . . the major suspects would be AF interstage coupling capacitors H and J, if opened up.
::
::
::Other check points:
::
::
::Confirm if a “sprung open “ headphone jack switching mechanism is not opening up the path of the output transformer to the speaker, as well as ohmically testing the speaker voice coil.
::
::
::
::
::
::Kasper Pee Clodddd, special LOW tech . . . yet highly effective . . . “seat of pants” test procedure:
::
::
::
::
::Take a 1K resistor and clip lead connect one of its leads to this sets main BEE minus . . . . notice I did's say BEE Minus-es-es-es supply, since this set is incorporating a cluster of "upside down and backwards" Pee Enn Pee transisto-mo-fers. .
::
::
::The other lead is then taken and used in a manner like the “quick striking of a match” to any of the multi commonly connected junctions of:
::
:: the center tap of the secondary of the driver transformer . . .or . . .
::
::
::Resistor R32. . .or . . .
::
::
::The Thermistor ( for temp comp) . . .or . . .
::
::
::Resistor R31 .
::
::
::Now if Tr-8 and Tr-9 are amplifying, that should result in a like burst of “scratch” noise emanating from the speaker.
::Move forward in the circuitry to Tr-7 transistor and perform the same “scratch test” on its BASE, but expect a much healthier aural response this time.
::
::
::Next test would be to “scratch” the BASE of the Tr-6 transistor stage and expect the loudest response yet.
::
::
::The final checks would be to run up the sets 5K volume control to its max volume position and “scratch “ both its rotor and high side terminal to verify that control, along with their responsive high level aural “scratches” coming from the speaker.
::
::
::That tests sequential completion should confirm the operationality of the audio chain on that unit, if BEE minus supply from the power supply and semiconductors---resistors---capacitors were all being O.K.
::
::
::If set is still inoperative . . .looks like RF is involved . . . will stand by at this time, awaiting your findings feedback.
::
::
::
::
::
::
::73's de Edd
::
::
::
::
::No time for a bath? . . . Simple . . . . just wrap yourself in masking tape and remove the dirt by simply peeling it off.
::
::
::
::
::
::
::
::
::
::
::
::
::
:: BX-326 Transistor Radio Schematic Mark-Up:
::
::
::
::
::
::
::
::
::
::
::
::
::
::
::
::
:::do you hear anything at all from the speaker.....hiss, static etc ? ...........or is it dead silent ?
:::
::
::
:::Now that you have the schematic do you have a signal tracer that you can use to find out where the signal appears or disappears ?
:::
:::
::
::
:
:
C37 was attached under the PC board. I clipped one of it's leads and "like Magic" the radio is working.
This is the mysterious thing that was connecting the collector to the junction of two components I was telling you about and shorting out the primary of the input transformer. A shorted capacitor. I guess this stumped whoever donated this to "Sal's".
I think it sounds fine without the capacitor. So I'm not going to replace it unless it will hurt something if it's not there.
Now I see that the D shaped end of the bolt that holds on the SW antenna has snapped off. I'll figure something out. But the radio is working quite well.
Thanks to all,
Dave
:
:
:
:
:
:
:
:
:
:
:
:
:
:Sir Dave. . . . .
:
:
:Well . . . . in initially perusing over the units design, ( its shematic DOOOOOOWN bee-low) we see no hi value output stage to speaker coupling capacitor in the mix.
:With the unit, instead, using old style transformer to speaker drive.
:
:
:In the lineup of its multi decades old electrolytic capacitors used . . .ref to mark-up . . . CAPS A-B-C-D are power supply filtering / decoupling related and shouldn't knock out the set.
:
:
:Same is true of the E-F’s , which are related to filtering the AVC buss and also should not knock out the set.
:
:
:Electrolytic G up in the TR-7 collector circuitry is tone control function related, but could result in gain loss if being excessively leaky.
:
:
:Electrolytic I, is serving as a partial emitter bypass for TR-6 could account for slight gain drain, along with an accompanying bass decline, if decreased way down in capacitance.
:
:
:AND THEN . . . the major suspects would be AF interstage coupling capacitors H and J, if opened up.
:
:
:Other check points:
:
:
:Confirm if a “sprung open “ headphone jack switching mechanism is not opening up the path of the output transformer to the speaker, as well as ohmically testing the speaker voice coil.
:
:
:
:
:
:Kasper Pee Clodddd, special LOW tech . . . yet highly effective . . . “seat of pants” test procedure:
:
:
:
:
:Take a 1K resistor and clip lead connect one of its leads to this sets main BEE minus . . . . notice I did's say BEE Minus-es-es-es supply, since this set is incorporating a cluster of "upside down and backwards" Pee Enn Pee transisto-mo-fers. .
:
:
:The other lead is then taken and used in a manner like the “quick striking of a match” to any of the multi commonly connected junctions of:
:
: the center tap of the secondary of the driver transformer . . .or . . .
:
:
:Resistor R32. . .or . . .
:
:
:The Thermistor ( for temp comp) . . .or . . .
:
:
:Resistor R31 .
:
:
:Now if Tr-8 and Tr-9 are amplifying, that should result in a like burst of “scratch” noise emanating from the speaker.
:Move forward in the circuitry to Tr-7 transistor and perform the same “scratch test” on its BASE, but expect a much healthier aural response this time.
:
:
:Next test would be to “scratch” the BASE of the Tr-6 transistor stage and expect the loudest response yet.
:
:
:The final checks would be to run up the sets 5K volume control to its max volume position and “scratch “ both its rotor and high side terminal to verify that control, along with their responsive high level aural “scratches” coming from the speaker.
:
:
:That tests sequential completion should confirm the operationality of the audio chain on that unit, if BEE minus supply from the power supply and semiconductors---resistors---capacitors were all being O.K.
:
:
:If set is still inoperative . . .looks like RF is involved . . . will stand by at this time, awaiting your findings feedback.
:
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:73's de Edd
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:No time for a bath? . . . Simple . . . . just wrap yourself in masking tape and remove the dirt by simply peeling it off.
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: BX-326 Transistor Radio Schematic Mark-Up:
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::do you hear anything at all from the speaker.....hiss, static etc ? ...........or is it dead silent ?
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::Now that you have the schematic do you have a signal tracer that you can use to find out where the signal appears or disappears ?
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Silence. As a matter of fact I do have a signal tracer.
Thanks,
Dave
:do you hear anything at all from the speaker.....hiss, static etc ? ...........or is it dead silent ?
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:Now that you have the schematic do you have a signal tracer that you can use to find out where the signal appears or disappears ?
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My EMC 802 tells me that the tuner is working fine. I "listen in" after the volume control and there's plenty of audio there. Plus I can adjust the volume control. Both BC and Short Wave are working great! So it's just a problem with connections in the amplifier section. There's one resistor with a lead pulled out of the board. Where it goes, I have no idea. I will have to study the parts view and schematic for several hours to be able to visualize it. No matter where I connected it, there's no audio. The resistor tests good. It's the correct resistance. But it must go somewhere. Someone tried to "repair" it but they gave up. But I think I can get it going. There doesn't seem to be very much wrong with it.
Thanks,
Dave
:do you hear anything at all from the speaker.....hiss, static etc ? ...........or is it dead silent ?
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:Now that you have the schematic do you have a signal tracer that you can use to find out where the signal appears or disappears ?
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Yes, and there's nothing there.
Dave
:Did you check the earphone jack ? Sometimes those can be open due to someone jamming the wrong plug in it. Also the wrong power supply may have been used, or with the wrong polarity. Check the audio output transistors.
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