no pilot light on a '60 ampeg b15
Moderators: pompeiisneaks, Colossal
no pilot light on a '60 ampeg b15
a buddy is dropping off his '60 b15 fro me to take a look at. he said the pilot light doesn't light and there is no sound. let's assume the rectifier and fuse are good at this point. what would you all check first? thanks, craig
Re: no pilot light on a '60 ampeg b15
I don't assume anything. test it and know.
Quick check. do the tubes light up (glow) if not that would explain why the bulb is not lit. - test the PT for heater voltage, could be a bad solder or shorted winding.
no sound... look at tubes, dead capacitors, blown OT. (i.e. not hookuped up to a speaker when powered on, tube failure, wrong impedance)
I'd put the tubes on the tube tester first, so i know.
while they are testing I'd test continuity on the fuse and bulb, or just replace them with known good ones.
put the amp on a variac and meter the amperage as I bring up the voltage if it's stable meter voltages through the circuit and see where it's shorted out.
If it spikes during the variac turn it off discharge, unsolder the PT leads and test for voltages to weed out the PT as the problem. test the filter caps, and look for any burned marks. Ampeg's are pretty good at showing where they fail.
If the PT is ok after you repair the rectifier and power filter section work through the circuit with a scope and test the OT.
if any of this is over your head, take it to a service tech, the old Ampeg boards are brittle and difficult to work on.
Quick check. do the tubes light up (glow) if not that would explain why the bulb is not lit. - test the PT for heater voltage, could be a bad solder or shorted winding.
no sound... look at tubes, dead capacitors, blown OT. (i.e. not hookuped up to a speaker when powered on, tube failure, wrong impedance)
I'd put the tubes on the tube tester first, so i know.
while they are testing I'd test continuity on the fuse and bulb, or just replace them with known good ones.
put the amp on a variac and meter the amperage as I bring up the voltage if it's stable meter voltages through the circuit and see where it's shorted out.
If it spikes during the variac turn it off discharge, unsolder the PT leads and test for voltages to weed out the PT as the problem. test the filter caps, and look for any burned marks. Ampeg's are pretty good at showing where they fail.
If the PT is ok after you repair the rectifier and power filter section work through the circuit with a scope and test the OT.
if any of this is over your head, take it to a service tech, the old Ampeg boards are brittle and difficult to work on.
Last edited by selloutrr on Sat Nov 05, 2011 7:29 pm, edited 1 time in total.
My Daughter Build Stone Henge
Re: no pilot light on a '60 ampeg b15
The very first thing that I do when opening up an ailing amp is to measure and record all voltages to get the lay of the land. This inlcudes both 120 V (in US models) PT primary points, B+ dropping string nodes and all tube pin voltages.
Nine times out of ten...this process identifies all "gross" issues and, at a minimum, provides a plan of attack for repair.
Having known working tubes on hand is also a tremendous time saver. Not to mention avoiding a lot of "hair pulling" if the problem is more subtle.
Good luck!
Dave O.
Nine times out of ten...this process identifies all "gross" issues and, at a minimum, provides a plan of attack for repair.
Having known working tubes on hand is also a tremendous time saver. Not to mention avoiding a lot of "hair pulling" if the problem is more subtle.
Good luck!
Dave O.
Re: no pilot light on a '60 ampeg b15
I agree but this assumes you can power the amp on to meter voltages. as well as having either a schematic to base your meter readings on or a solid understanding of the circuit you are diagnosing. Known good tubes are a huge time saver!ampgeek wrote:The very first thing that I do when opening up an ailing amp is to measure and record all voltages to get the lay of the land. This inlcudes both 120 V (in US models) PT primary points, B+ dropping string nodes and all tube pin voltages.
Nine times out of ten...this process identifies all "gross" issues and, at a minimum, provides a plan of attack for repair.
Having known working tubes on hand is also a tremendous time saver. Not to mention avoiding a lot of "hair pulling" if the problem is more subtle.
Good luck!
Dave O.
My Daughter Build Stone Henge
Re: no pilot light on a '60 ampeg b15
o.k., at first glance it looks like the power switch may be bad. it is the old rotary, 4 position version. i emailed fliptop amps to see if they have a replacement. any other places you guys would suggest? thanks.
Re: no pilot light on a '60 ampeg b15
Test it with continuity what are the manufacture markings?
I'm not fully following you. The b-15 power is a toggle switch on off. Ground on off and standby on off. Are you looking at a voltage selector? Export model?
Pics?
I'm not fully following you. The b-15 power is a toggle switch on off. Ground on off and standby on off. Are you looking at a voltage selector? Export model?
Pics?
My Daughter Build Stone Henge
Re: no pilot light on a '60 ampeg b15
this is a very early one, june 1960. the power switch is a rotary 4 position type. off-standby-on+on-.
i'll post a pic later. thanks.
i'll post a pic later. thanks.
Re: no pilot light on a '60 ampeg b15
front pic
[img
768]http://i10.photobucket.com/albums/a131/ ... 0881-2.jpg[/img]
back pic
[img:897:1024]http://i10.photobucket.com/albums/a131/ ... 0882-2.jpg[/img]
[img
768]http://i10.photobucket.com/albums/a131/ ... 0881-2.jpg[/img]
back pic
[img:897:1024]http://i10.photobucket.com/albums/a131/ ... 0882-2.jpg[/img]
Re: no pilot light on a '60 ampeg b15
That's an early model!
Draw it out and test continuity note where wires go and what they connect to.
That switch is no longer made as an official Ampeg part. I own several '60's B-15(n/s) B-18.. and repaired a fair number That is the first I've seen with a rotary power.
With that said. That switch or one that will work is still made by another manufacture such as Mallory or lorlin.
It looks like they tied the lugs together to increase handling voltages.
If you can document the switch and what exactly it is set up to do finding a replacement is easy.
How many lugs go around the outside?
How many in the center?
Draw it out and test continuity note where wires go and what they connect to.
That switch is no longer made as an official Ampeg part. I own several '60's B-15(n/s) B-18.. and repaired a fair number That is the first I've seen with a rotary power.
With that said. That switch or one that will work is still made by another manufacture such as Mallory or lorlin.
It looks like they tied the lugs together to increase handling voltages.
If you can document the switch and what exactly it is set up to do finding a replacement is easy.
How many lugs go around the outside?
How many in the center?
My Daughter Build Stone Henge
Re: no pilot light on a '60 ampeg b15
Most likely a 3 pole 4 position switch
I can't copy the link on my phone's eBay app but I did find several that would work for around $10 each.
If you search 4 position 3 pole switch you should find what you are looking for.
I can't copy the link on my phone's eBay app but I did find several that would work for around $10 each.
If you search 4 position 3 pole switch you should find what you are looking for.
Last edited by selloutrr on Sat Nov 05, 2011 10:59 pm, edited 1 time in total.
My Daughter Build Stone Henge
Re: no pilot light on a '60 ampeg b15
12 poles on the outside, 3 poles on the inside. front of switch is labeled "made in the usa" 3612 8 and 467. thanks.
Re: no pilot light on a '60 ampeg b15
3P4T rotary switch
make sure the switch is rated to handle the 120VAC.
http://search.digikey.com/scripts/DkSearch/dksus.dll
make sure the switch is rated to handle the 120VAC.
http://search.digikey.com/scripts/DkSearch/dksus.dll
My Daughter Build Stone Henge
Re: no pilot light on a '60 ampeg b15
is 2.5a enough? like this one?
http://search.digikey.com/us/en/product ... -ND/483970
http://search.digikey.com/us/en/product ... -ND/483970
Re: no pilot light on a '60 ampeg b15
what is the amp draw of the amp?
What's the fuse rating?
What's the fuse rating?
My Daughter Build Stone Henge
Re: no pilot light on a '60 ampeg b15
the circuit calls for a 3a. currently my friend has a 2a in there. i haven't told him yet. 