Watts Hold lamp dim

[Gregory]

This relates to the amplifier refurb topic. It seems after replacing all of the #7381 and #7382 bulbs on the Lamp PC Board, the Watts Hold lamp is still dim, ~50% or less of the other two power lamps. I now believe that D120 may in fact be defective. Does that make sense?

Also.. what role do D302 and D303 play on the Power Supply board between the 2200uF caps? I think it would be good to replace all of those 1.5A rectifiers it you so agree/advise.

-Gregory

[dewickt]

Yes, the watts hold lamp should be dimmer, don't know why they did it this way but this is how it should be.
The 2 caps and 2 diodes are set up as a voltage doubler, they take 6.3VAC and give a 12VDC output to drive the lamps.

[Vintage Pete]

Gregory...I didn't replace D120 (or anything on the lamp board). My problem lied solely with the power supply board, the two caps and possibly the diodes.

Terry...I never noticed the watts hold lamp being dimmer-I had to turn on my 2205 just now to verify. Indeed it is-but only slightly so. I wouldn't say 50% dimmer....but that's just to my eyes....???

I replaced D302 and D303 becuase you'd advised another fellow with the same issue with his 2125 to do so. Since it appeared to me to be essentially the same circuit, I applied your advice to my 2205. BTW, I had been perplexed as to why my lamps didn't function...I figured it wasn't the bulbs though, because I tested the voltage coming in to them , and there wasn't any.

Pete

[Gregory]

Originally Posted by Vintage Pete

Gregory...I didn't replace D120 (or anything on the lamp board). My problem lied solely with the power supply board, the two caps and possibly the diodes.

Terry...I never noticed the watts hold lamp being dimmer-I had to turn on my 2205 just now to verify. Indeed it is-but only slightly so. I wouldn't say 50% dimmer....but that's just to my eyes....???

I replaced D302 and D303 because you'd advised another fellow with the same issue with his 2125 to do so. Since it appeared to me to be essentially the same circuit, I applied your advice to my 2205. BTW, I had been perplexed as to why my lamps didn't function...I figured it wasn't the bulbs though, because I tested the voltage coming in to them , and there wasn't any.

Pete

Pete.. one of my green Power Guard lamps on the 2205 was out and the amber Hold lamp was dim. I had planned to change out ALL of the 2205 lamps anyway from the git-go. The original GE #1866 bulbs were all cruddy (filmy) and tarnished. The new ones were nice shiny bright metal.

If you have the front panel off the 2205 and pull the white rubber `seat´ that holds the power indicator bulbs in place, then you'd clearly see the lower intensity of the Hold lamp. I took a photo of it but the filament brightness washed out the image. Maybe when in there next time, it would be good to measure and note some voltages.

Now that Terry says the center lamp is normally dimmer, I no longer suspect D120 to be bad, or D302, D303 either. Had planned to order some replacement diodes from Mouser anyway to have them here on hand. Mc Parts says the 16V Zeners are 1N5246B. However it might be good to consider when to apply the rule: Ain't broke.. don't fix it.

-Gregory