Dr. Z Maz Sr. Blowing Fuses!! Help!

[guitarboy373]

Last night my Maz 38 Sr. Reverb starting blowing the 3 amp fuse repeatedly. I went through 5 in a matter of 3 hours. I think it has to do with the fan, both times I wiggled the fan plug it blew the fuse immediately. Then I left the fan unplugged and the amp was fine for the remaining 30 minutes I had it turned on.

Any thoughts on this? Any tests I can run?

Thanks guys!

Jordan

[guitarboy373]

Latest findings...everytime I put a new fuse in, I turn the standby on to warm it up, and then as soon as I power it up there's an electrical arc inside the rectifier tube and that's when the fuse blows. Any thoughts?

[bilbal]

First do not be alarmed. I know that's easier said than done. I and a bunch of others at the ZForum have had this problem. You need to changed out the rectifier tube. The rectifiers that come stock in the Maz amps are not that great. I had the same problem as you are having and I thought my amp was toast. It just kept blowing and I got extremely nervous. Much the same as you. Swap out the stock rectifier tube with a NOS tube from KCA. I put a Jan Philips / Sylvania in my MazSr and it's been perfect since. The same thing happened with my brand new Galaxie, it was changed also.

here's the link and RELAX it will be fixed in no time my friend:
http://kcanostubes.com/categories/213/1/JAN-Philips-Sylvania.htm

The rectifier fireworks is the clue. As you said you saw it arc. Very simple fix!!!!!

Have a look at this thread at the ZForum
http://drzamplifiers.proboards41.com/index.cgi?board=Maz38&action=display&thread=1178062115

http://drzamplifiers.proboards41.com/index.cgi?board=xperts&action=display&thread=1175430772

[Blue Strat]

Thanks Bilbal.

It's odd that the fan seems to be related to the problem. Since the fan isn't stock, how exactly do you have it connected?

The arcing rectifier could be a rectifier problem OR a another problem that's causing the rectifier problem. One way to find out is to get another (better) rectifier as per Bilbal. You'll need another one soon enough.

[guitarboy373]

Good deal, thanks guys, I pulled out the rectifier and here it's a Ruby tube, BLAH! I'm going to go pick up a Groove Tube 5AR4 today and put that in it and see what happens. I'll let ya'll know how it works!

[bilbal]

Thanks Bilbal.

It's odd that the fan seems to be related to the problem. Since the fan isn't stock, how exactly do you have it connected?

The arcing rectifier could be a rectifier problem OR a another problem that's causing the rectifier problem. One way to find out is to get another (better) rectifier as per Bilbal. You'll need another one soon enough.

Mike:
It's never a problem giving respect and props whenever due. You certainly deserve it my friend as you helped me out of a bind and did with class and a speedy delivery. There's no doubt I will come back to you when/if I need a similar problem fixed in the future.

take care Mike,
Bill (bilbal

[Blue Strat]

Good deal, thanks guys, I pulled out the rectifier and here it's a Ruby tube, BLAH! I'm going to go pick up a Groove Tube 5AR4 today and put that in it and see what happens. I'll let ya'll know how it works!

Note that neither Ruby or Groove Tubes make rectifiers. They buy and relabel cheap Chinese and Russian tubes. The Groove Tube you buy may in fact be identical to the Ruby you're replacing.

[Blue Strat]

Mike:
It's never a problem giving respect and props whenever due. You certainly deserve it my friend as you helped me out of a bind and did with class and a speedy delivery. There's no doubt I will come back to you when/if I need a similar problem fixed in the future.

take care Mike,
Bill (bilbal

Happy to help!:BEER

[guitarboy373]

Hey guys, got a new rectifier for the Z yesterday before a gig, put it in and she sang her heart out the whole way through the show. So hopefully the problem is fixed up! So far so good anyways. Thanks for your help!

[bilbal]

I'm glad I could be of some assistance. Feel better now don't ya?!!!