Kustom 72' coupe

fiddlemandwayne · 11-08-2009, 08:12 PM

My amp just fried and i believe it was the two bias resistors R102 &R101 I cannot find out what the value and wattage is of these two resistors becouse they were chared. These amps get real hot becouse of the tubes so I put two computer fans on it to keep it cool ,but I forgot to turn it on this time.Has anyone else had a problem similar to this ? It would get so hot ,you could not keep your hands on it for more than 3-4 seconds.
Thanks!
Dwayne

tartanphantom · 11-18-2009, 08:30 PM

Sorry to hear about this. The Kustom Coupes are awesome sounding amps, but they are prone to high temp issues because of the biasing scheme.

I haven't had a burnout, but my Coupe used to get so hot that the trem/vibe circuit would stop working. Like you, I installed a small multi-speed twin computer fan on the power tube cage. Once I did this, no more problems! I think these amps should come with a cooling fan as standard equipment.

Sorry I can't help you on the schematic, but if you email Kustom, I understand that they will send you a pdf schematic, but they will also caution you that it will void your warranty. So if yours is still under warranty (mine is not) you'd be better off sending it to an authorized service tech.

gtrdon · 11-26-2009, 02:19 AM

I replace those two resistors with 100 ohm 10 watt ceramic resistors,Also don't forget the two 47uf 100 volt electrolytic caps.One more thing to check are the 4.7k input grid resistor that go to pin #5 on the out put tubes.a quick and dirty test is to locate pin 5 and check for -25 vdc on all power tube sockets if so chances are the grid resistors are fine.The 100 ohm resistors help to lower the heat.thecorrect resistors are 82 ohm 10 watt.

11-08-2009, 08:12 PM	#1
fiddlemandwayne Junior Member Join Date: Nov 2009 Location: white,georgia Posts: 1	Kustom 72' coupe schematic My amp just fried and i believe it was the two bias resistors R102 &R101 I cannot find out what the value and wattage is of these two resistors becouse they were chared. These amps get real hot becouse of the tubes so I put two computer fans on it to keep it cool ,but I forgot to turn it on this time.Has anyone else had a problem similar to this ? It would get so hot ,you could not keep your hands on it for more than 3-4 seconds. Thanks! Dwayne Last edited by fiddlemandwayne; 11-09-2009 at 05:06 AM. Reason: found typo and to ad more info

Thread Tools
Show Printable Version Email this Page
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
36 coupe filament problem	jeffsjazz	Maintenance, Troubleshooting & Repair	5	08-14-2009 06:17 AM
Kustom '36 Coupe	Euthymia	Schematic Requests	1	04-30-2009 09:22 AM
Any info on the new Kustom Coupe 72 amps?	Steve A.	Guitar Amps	2	03-13-2008 01:36 AM
Arcing in a '72 univox	Doug	Maintenance, Troubleshooting & Repair	0	08-05-2007 02:57 AM
72 Princeton overhaul?	sgmarshall	Mods & Tweeks	2	08-09-2006 03:30 AM

11-18-2009, 08:30 PM	#2
tartanphantom Junior Member Join Date: Oct 2009 Location: Murfreesboro, TN Posts: 1	Sorry to hear about this. The Kustom Coupes are awesome sounding amps, but they are prone to high temp issues because of the biasing scheme. I haven't had a burnout, but my Coupe used to get so hot that the trem/vibe circuit would stop working. Like you, I installed a small multi-speed twin computer fan on the power tube cage. Once I did this, no more problems! I think these amps should come with a cooling fan as standard equipment. Sorry I can't help you on the schematic, but if you email Kustom, I understand that they will send you a pdf schematic, but they will also caution you that it will void your warranty. So if yours is still under warranty (mine is not) you'd be better off sending it to an authorized service tech.

11-26-2009, 02:19 AM	#3
gtrdon Junior Member Join Date: Oct 2008 Location: North Carolina Posts: 4	I replace those two resistors with 100 ohm 10 watt ceramic resistors,Also don't forget the two 47uf 100 volt electrolytic caps.One more thing to check are the 4.7k input grid resistor that go to pin #5 on the out put tubes.a quick and dirty test is to locate pin 5 and check for -25 vdc on all power tube sockets if so chances are the grid resistors are fine.The 100 ohm resistors help to lower the heat.thecorrect resistors are 82 ohm 10 watt.

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)