sansui 8000 blowing lights

[maclvrbr]

recently acquired and it needed all 4 dial- meter lights. Looked great after a week 1 went out. I replaced that one a week later 3 of them went out. Any ideas? 6volt 250 ma.

 

[Robisme]

Supposed to be 8 volt 300ma lamps. 6 volt lamps wont last.

Rob

 

[maclvrbr]

My mistake I rechecked my stash and they are 8v 300ma I used to replace with. I checked the SM and it suggest the original was 8v, ideas and thanks

 

[w1jim]

Measure the actual voltage at the lamps.

 

[maclvrbr]

will do and thanks

 

[maclvrbr]

I am getting 9.5 ac volts at the 2.5 amp fuse feeding the lamps

 

[LBPete]

Is this a G-8000? If so, the lamp voltage feed should be 7.5v AC, 9.5V AC is a bit troubling. Where are you located? Is the input voltage selector set correctly? Do you have unusually high line voltage in your house?

Please post the serial number for the database. Click on the link in my signature block.

- Pete

 

[Robisme]

What Pete said.

If all that is fine, you may have to go to 12 volt lamps, if you can find some.

Rob

 

[LBPete]

NO, don't just go to higher voltage lamps! If that transformer output is high, it's likely all of them are high. If my first suggestions don't turn anything up, you need to check all the transformer output. The dial lamp bulbs may be the canary in the coal mine.

- Pete

 

[maclvrbr]

The input selector is correct. at 120v and does have the option for 220v. I do not have an unusually high voltage in my area. Central alabama. Ideas? thanks

 

[LBPete]

You need to check the voltage of all of the transformer taps. Measure the AC voltage at all of the fuses on the power supply board F-2807. You need to determine if just the lamp supply is high or are other transformer output voltages high. This is a G-8000 right?

- Pete

 

[maclvrbr]

It is a G801 I thought it was the same receiver. It does have a multi voltage selector and confirmed it to be in 120v. Will do on the voltage check

 

[Robisme]

The dial lamp power comes directly from a secondary winding of the transformer. If the input voltage is correct, there is not much you can do.

Follow Pete's advise though.

Rob

 

[w1jim]

The voltage will probably read higher with no load on it - try reading the voltage with some bulbs in it.
You can get replacements bulbs (8 and 12 volt) at Parts Express.
Personally, I'd put LEDs in.
https://www.parts-express.com/cat/fuse-type-lamps/1406

 

[maclvrbr]

I checked the fuse voltage as before ACV is 9.5 at F-03, F-02 and F-01 are 55.5 ACV. That voltage is taken with only 1 of the 4 lamps working at this time the other 3 were blown.

 

[maclvrbr]

The lamps are round with leads out of 1 end but thanks

 

[w1jim]

Oops, all this talk of fuses somehow I incorrectly thought they were fuse bulbs.
You could always put in a simple voltage regulator or voltage divider to drop the bulb voltage.

 

[maclvrbr]

How can I do that very interesting

 

[w1jim]

You can read about voltage dividers:
https://learn.sparkfun.com/tutorials/voltage-dividers

Looking at the schematic this circuit also feeds the LED indicator lights. Personally I’d just try to find some 10-12 volt bulbs that would fit.

 

[maclvrbr]

Dwojo said his long lasting 8v lamps work up to 14 acv. Thanks