Sherwood 7100 Stereo Indicator bulb keeps frying.

[Keneye]

I have a stereo 7100 driving me nuts. Plays fine. But the stereo indicator bulb was blown. Put in a new bulb and it blew. Meter says it is getting 30v which fades to less than 1v. The bulb is 8v .3ma. Since the voltage bleeds off, I am thinking capacitor.
Anyone ever had a similar issue? Board voltages seem to be normal but documentation for voltages is sparce.

 

[Ylli]

The bulb is nominally 8v 30 mA. If all is well, the resistive divider of R664 and R655 will limit the bulb current to a max of about 35 mA. I would check for an open R665.

 

[Keneye]

Thanks. Will do! I appreciate the help!

 

[Keneye]

The bulb is nominally 8v 30 mA. If all is well, the resistive divider of R664 and R655 will limit the bulb current to a max of about 35 mA. I would check for an open R665.
View attachment 2399553

Hi, do you mean 655?

 

[goat67]

yes I believe he did

 

[Ylli]

yes

 

[llwhtt]

What happened to the original post? 7100 OR 7100A, the Stereo lamp circuit is different between the two.

 

[Ylli]

Good catch Craig. I know they are different, and I was sure I pulled the 7100 manual, but looking now I had the 7100A manual.
Keneye, disregard what I posted.

 

[Keneye]

Good catch Craig. I know they are different, and I was sure I pulled the 7100 manual, but looking now I had the 7100A manual.
Keneye, disregard what I posted.

Yes. I have 7100. So far, all resistors test fine. Even had an electronic tech friend look at it. The one ceramic resistor R801 is super hot. Not even listed on parts list. Documentation is lacking.

 

[Ylli]

If R801 is extra hot, there may be an issue with the +12/+36.5 voltage regulator. Take a look at the attached and check the indicated voltages. (yes, this is definitely out of the 7100 manual.)

 

[Keneye]

They test ok! Replacing anyway. Waiting to arrive. Maybe they get wonky under load.