dear friends hello!! i am from Greece and this is my first post in this website.
I would kindly like to ask for your help. In some days i am receiving my MF B200X from Germany. I have read your posts and also mr.henesis' website and i got excited. The problem is that i am not familiar with electronics, but i can find a friend who can solder. I have a friend who is an electrician. can you please write me in 2-3 lines what parts to order to "refresh" my amp. The parts that someone can easily change with a reasonable cost to revive this wonderfull amp. Thank you very very much in advance...i will be waiting for your answears.
I would kindly like to ask for your help. In some days i am receiving my MF B200X from Germany. I have read your posts and also mr.henesis' website and i got excited. The problem is that i am not familiar with electronics, but i can find a friend who can solder. I have a friend who is an electrician. can you please write me in 2-3 lines what parts to order to "refresh" my amp. The parts that someone can easily change with a reasonable cost to revive this wonderfull amp. Thank you very very much in advance...i will be waiting for your answears.
The capacitors you've found will need a bit of work to fit, the originals are 25mm in diameter.
I just restored an B200 and the sound is great after setting the right quiescent current.
Many thanks to Jez for helping.
Parts used from Farnell:
4 x ESMH630VSN682MQ50T
2 x EEUFM1E221
4 x EEUFC1J101
4 x EEUFC1H100
1 x FAIRCHILD SEMICONDUCTOR - GBPC2504 - BRIDGE RECTIFIER, 25A, 400V
Check for bad soldering, look for grainy/yellow/brown solder affected by heat. I resoldered 30-40% of the board.
I would recommend PS capacitors with a greater voltage than 63V but I haven't found anything to fit.
Good luck!
I just restored an B200 and the sound is great after setting the right quiescent current.
Many thanks to Jez for helping.
Parts used from Farnell:
4 x ESMH630VSN682MQ50T
2 x EEUFM1E221
4 x EEUFC1J101
4 x EEUFC1H100
1 x FAIRCHILD SEMICONDUCTOR - GBPC2504 - BRIDGE RECTIFIER, 25A, 400V
Check for bad soldering, look for grainy/yellow/brown solder affected by heat. I resoldered 30-40% of the board.
I would recommend PS capacitors with a greater voltage than 63V but I haven't found anything to fit.
Good luck!
Does anyone know what the transformer is for the B200. I have a B200 with a dead transformer, I have contacted Musical fidelity with no help from them and I have contacted most of the dealers on there web page To be told they will find out and never ring me back. all together I have been waiting 8 months to fix it.
Any help would be much appreciated.
Any help would be much appreciated.
*bump*
The transformer in these is much too small to provide the quoted 60W per channel. I've just got one with a broken Tx, shorted turn on the primary. It's 40mm high and 90mm diameter, which is about 80VA. I'm thinking a 35-035 AC would be adequate, any thoughts?
All the TO3 MOSFETs have failed. One of them pretends to work but I don't trust it. Shall I fork out £50 for non-Hitachi ones or replace them with the plastic version, much cheaper. Part of me wants to keep the integrity of this amp but the other part isn't very impressed with the construction.
This is a class AB design, also used in the later A1, so I don't think the top should get hot at all. The quiescent current suggested earlier seems a little high. Is this MF's way of convincing people it's doing something? 120v at 100mA is 12 watts per channel, totally unnecessary heat. And that's not good for the electronics. I'd suggest 50mA or less and challenge anyone to tell the difference.
It's also got some botched extra heavy duty earth cable run all over the board. Has anyone experienced any hum problems or something to explain these? It's also got botched source resistors on one channel. A bit of a mess really.
It looks really cool though.
The transformer in these is much too small to provide the quoted 60W per channel. I've just got one with a broken Tx, shorted turn on the primary. It's 40mm high and 90mm diameter, which is about 80VA. I'm thinking a 35-035 AC would be adequate, any thoughts?
All the TO3 MOSFETs have failed. One of them pretends to work but I don't trust it. Shall I fork out £50 for non-Hitachi ones or replace them with the plastic version, much cheaper. Part of me wants to keep the integrity of this amp but the other part isn't very impressed with the construction.
This is a class AB design, also used in the later A1, so I don't think the top should get hot at all. The quiescent current suggested earlier seems a little high. Is this MF's way of convincing people it's doing something? 120v at 100mA is 12 watts per channel, totally unnecessary heat. And that's not good for the electronics. I'd suggest 50mA or less and challenge anyone to tell the difference.
It's also got some botched extra heavy duty earth cable run all over the board. Has anyone experienced any hum problems or something to explain these? It's also got botched source resistors on one channel. A bit of a mess really.
It looks really cool though.
You have stated broken output transistors, broken transformer and described as botched everything else.
Based on the above, it is not worth repairing.
*sad emoji*
Thanks Andrew, I was heading that way. Pity really, it's an interesting design let down by using too small a transformer. I don't even want to use a lower voltage one, it would still be underrated and dodgy. One answer would be to use an external Tx, if I was a fan of these things. I'll cut my losses and keep well away from MF.
Thanks Andrew, I was heading that way. Pity really, it's an interesting design let down by using too small a transformer. I don't even want to use a lower voltage one, it would still be underrated and dodgy. One answer would be to use an external Tx, if I was a fan of these things. I'll cut my losses and keep well away from MF.
- Status
- Not open for further replies.