Microtube 100 questions

[El Chiguete]

Since I don't see a Microtube 100 section (only the Microtube 200 section) I will write in here... maybe you guys should make a Microtube 100 section too.  ;)

Anyway I've had a Microtube 100 that I bought together with my MP-1 years ago. When I bought it it was all good, then one channel stoped working and a friend fixed it, then the other stoped working and my friend don't want to fix it because he says that they just will continue doing that. So for the last like 1-2 years I've been using another amp but I still miss the sound of the stereo chorus on my MP-1 and today I decided to give it a try not just for the stereo chorus but to try a wet/dry setup! I started with the W/D setup and I was liking it for like 15min but before I could do something else it stoped working  :dunno:. Now here is the thing, I poped it open and notice that the 2 channel fuses where blown ??? I don't know if one blew off just because the light when off and the inverted came on or because I was experimenting with the INs and OUTs connections, so me questions are:

1) do the Microtube series needs to have something plugged din to its output like a valve amp or it doesn't like a SS amp?
2) if it needs to have something pluged in the outs how do I try different settings: do I need to turn off the channel volume first?
3) would a fuse blow when the light went off and the inverter turned on? btw the main fuse and the other fuse that is connected close to it are ok.
4) what would be the correct values for the fuses?

[MarshallJMP]

There are 2 3A fast fuses for the power amps,if these blow it usually means one of the power mosfets is busted.There should also be a mains fuse,usually the value is printed near the fuse holder.

[El Chiguete]

Yeha the main fuse is ok the other two are busted (but dont know if both did it today or one was blown from before). I just wanted to check the they where supposed to be 3A and that I don't buy based on the ones there because they might had been changed before. BTW, any 3A fuse works or is there a specific type of 3A fuse that I should get?

Also, how can I check to see if the power mosfets are busted? I believe they are the 2 outer parts that I have in the red circles A1 and A2 yes (IRF9530 and IRF530?

PS:
What's the part number MPS8099 between them? and whats part number 7912 under circle B?

[El Chiguete]

Also can you comment on these questions I made:

1) do the Microtube series needs to have something plugged din to its output like a valve amp or it doesn't like a SS amp?
2) if it needs to have something pluged in the outs how do I try different settings: do I need to turn off the channel volume first?
3) would a fuse blow when the light went off and the inverter turned on? btw the main fuse and the other fuse that is connected close to it are ok.
4) what would be the correct values for the fuses?

[rnolan]

Hey El, those 2 fuses are 3A "fast blow" fuses as opposed to slow blow.

1) do the Microtube series needs to have something plugged din to its output like a valve amp or it doesn't like a SS amp?
Not sure what you mean here, MT100 outs go to speaker cabs. Moreover, they are a hybrid power amp, tube input, SS (mosfet) output
2) if it needs to have something pluged in the outs how do I try different settings: do I need to turn off the channel volume first?
Its always a good idea to either turn off, or at least turn down channel vol when plugging speaker in and out (or inputs)
3) would a fuse blow when the light went off and the inverter turned on? btw the main fuse and the other fuse that is connected close to it are ok.
Hard to say, maybe (MJMP/Sparker etc will know better than me), I do know my MP2s don't like generators and when they get shitty power, they crap out and need a power cycle to fix, I now use a small UPS (not a bad solution for you maybe, I bought a 1KVA for around $160)
4) what would be the correct values for the fuses?
As MJMP advised, 3A fast blow (which may be why they popped with the hybrid power ?)

But from what MJMP says, the power mosfets are probably gone (cheep test is replace the fuses and see if they blow again), otherwise sounds like the fix is new power mosfets (and I believe your circles are in the right place :thumb-up: ) and fuses.

[MarshallJMP]

The mps8099 is a small NPN transistor mounted on the heatsink to compensate the current when the unit gets hot.

The 7912 is a -12V regulator.

nothings needs to be plugged in.

[El Chiguete]

Marshall: Do you have those mosfets that I could pick up when I meet you?

[El Chiguete]

Ok so havent been able to try out new fuses on my Microtube 100 until now and as soon as I turn it on both of them went caput!!! This meens that I need new mosfets... where can I buy them?

[El Chiguete]

Are these them?

http://www.mouser.com/Search/ProductDetail.aspx?R=IRF9530virtualkey61370000virtualkey844-IRF9530
http://www.mouser.com/Search/ProductDetail.aspx?R=IRF530virtualkey61370000virtualkey844-IRF530

[MarshallJMP]

Are these them?

http://www.mouser.com/Search/ProductDetail.aspx?R=IRF9530virtualkey61370000virtualkey844-IRF9530
http://www.mouser.com/Search/ProductDetail.aspx?R=IRF530virtualkey61370000virtualkey844-IRF530

Yep these are the correct ones.But i would also replace all the driver transistors,if one of these is bad you can end up with 2 busted power fets again.

[El Chiguete]

So how do I look for the driver transistors? what are their parts numbers?

[MarshallJMP]

These are Q2,3,4 and 5 for the A channel and Q102,103,104 and 105 for the B channel.

Q2,4 and 5 are MPS8099 or BC546 but these have a different pinout and you need to install them turned 180 °(C and E are switched)  mouser partnr 863-MPS8099G

Q3 is a MPS8599 or a BC556 again these need to be turned.

Mouser doesn't seem to carry the 8599 anymore but they have the bc556 512-BC556ABU

See pdf

[El Chiguete]

Ok so when I do a search for MPS8099 I get all of this different choices http://www.mouser.com/Semiconductors/Discrete-Semiconductors/Transistors/Transistors-Bipolar-BJT/_/N-ax1sh?Keyword=MPS8099&FS=True

Since I don't want to screw up more my unit can you gave me the correct mauser part numbers for all of the parts I need to buy? Sorry for not knowing all this transistors/electric language to know what to use.

[MarshallJMP]

I have put the mouser nr in my previous reply

863-MPS8099G

512-BC556ABU

[El Chiguete]

So this would be the correct final list?