Heathkit w4am restoration No Sound

Hi John. I've looked at your pictures and a few things stand out:

- You have a long length of twisted bare copper wire flying over the top of energized circuitry (not good!).
- In photo #3, that bare wire appears to be touching the 2.2k resistor as it bends toward the bottom of the photo.
- In photo #3, the end of the bare wire appears to be connected to a lug but not soldered.
- In photo #2, left edge, center, there appears to be an uncut pigtail from the solder lug touching the chassis.
- Photo #3, center tube socket, it looks like an accident waiting to happen.
- Photo #3, right under the bare wire there's a black wire soldered to two resistors, the joint uninsulated and floating, could touch the chassis!
- Numerous instances of melted insulation near solder joints
- Don't use electrolytics if the schematic doesn't call for them. Mouser, Digi-Key, and Antique Electronic Supply have high voltage non polarized caps.

I'm not trying to be critical of your work but you should consider whether certain sections should be re-worked. Resistors and wire are cheap.
Since you've caused a "great disturbance in the force" so to speak by rebuilding, you have to assume that you made a mistake somewhere. Photocopy your schematic. Go through the copy with a marker pen and trace the circuit carefully to make sure every connection, branch, and component value matches the schematic. Mark the drawing as you go. Hopefully something will jump out at you and will be easily corrected.

As other members have noted, measure your voltage test points to see if they look right. I'm eager to hear of your success!

See my own restoration thrills and chills at: aa100restoration.wordpress.com/
 
I just checked the voltages. There was a floating ground lurking in the chassis while that gave the preamp power,still very low volume out of a maggie 4ohm 8inch speaker. And when i say low i mean my phone has a higher volume half way turned up, without amplification. voltages tested about 20 percent higher despite the line voltage being 117 volts exactly after the thermistor. Im stumped. I will go through resistors in the power supply checking tolerances.
John
 
Back
Top Bottom