Mark III fuse replacement - HELP!

[inhalingsounds]

Hi guys,

I have a Mark III (Green Stripe) and my slow-blo fuse has blown. I am in a rush because I have a gig coming up and I need to replace it ASAP, but I'm having trouble trying to find the exact specs of it so I can ask it in a local store. Should I just ask for a slow-blo 3A fuse, or is there anything else?

Thanks in advance!

 

[MrMarkIII]

3A Slo-Blo. Radio Shack. Made by Littelfuse. Pack of 5.
Fuse blowing is a symptom, not the disease. Replacing the fuse doesn't "cure" the problem.
What happened just before the fuse blew?

 

[inhalingsounds]

Yup, I know, but for this gig it will "fix" it because the problem was not directly related. Anyway, I think this is the best place to discuss it, so here goes.

I bought a PAlmer PDI-03 - http://www.thomann.de/pt/palmer_pdi_03l4.htm so that I could play with headphones (amp > palmer > audio interface > phones) or record the amp (amp > palmer > audio interface > computer).

I was advised I should buy the 4 OHM version, as I could connect it to one of the speaker outputs (there are two, each marks 4 OHM), and disconnect the speaker (8 OHM) - the Palmer acts as load box, as well as a speaker sim. However, after playing for a few minutes, fuse blown. I'm really hoping it's just the fuse ...

Question: is the 4 ohm the correct version? Or should it be the 8 ohm, connected DIRECTLY on the speaker output? I can still ask for a refund on the 4 ohm and replace it ... Hope someone can help!

 

[nor]

There is an 8ohm jack there as well.
:wink:
I would have went with the 8. That being said, MkIII's are usually very tolerant of mismatched loads. If you had the amp cranked, and the Palmer attenuation cranked - that absolutely puts a major load on ALL of your amps internals. Especially the power tubes. Buy more than one fuse, make sure you have backup power tubes. Very good chance you dinged a power tube which in turn blew the fuse.

 

[MrMarkIII]

Manuals are available free at the Mesa website.
Those two 4 ohm speaker jacks are designed to take an 8 ohm load (each), not a single 4 ohm load. Mesa expects you to plug one 8 ohm cab into each one of those 4 ohm jacks, and *not* use the single 8 ohm jack in this case.
Yes, it is confusing. Well, not any more, as it has now been explained.
I would get the 8 ohm Palmer.

 

[okgb]

8 ohm out into the 4 ohm would create a strain but 4 into 4 or 8 into 8 should be the same , no ?
It may not be practical to sell & rebuy the palmer , also a drag to keep buying fuses , check the output
tubes if you can , or sub fresh ones if you have , if no test gear and you have the time , could open it
up and double check the output tubes for any burnt resisters , good luck , let us know