Lux91 Mono Max - Technical Help Required

[Chromene]

I could use some technical help. I have some relatively new Lux91 Mono Blocks (arrived in March). The amps have been fantastic until yesterday when one channel cut-out. I checked the fuse and it had blown. I have since replaced the fuse a couple of times and it immediately blows when the switch is turned on. I removed all tubes and inserted a new fuse and it still blows every time I turn the amp on. I have visually inspected the internals and nothing looks to be out of the ordinary. Can anyone walk me through some quick checks /diagnostics to isolate the problem.

Any help would be greatly appreciated.

Thanks

 

[ThorstenL]

Hi,

I could use some technical help.

Please directly contact diyhifisupply in the first instance.

You could try removing the 300B and rectifier tube, replace the fuse and see if it blows again.

Ciao T

 

[Chromene]

Thorsten,

Thanks for your response. I did remove all tubes and the fuse still blows.

Does it make a difference if I only remove the rectifer and the 300b and leave the driver tubes.

Thanks,
CD

 

[rolls]

Thorsten,

Thanks for your response. I did remove all tubes and the fuse still blows.

Does it make a difference if I only remove the rectifer and the 300b and leave the driver tubes.

Thanks,
CD

Hello
a friend of me had similar problems with the new MonoMax, now half a year later the amps work flawlessly.
If the fuse break immediately after turn on, I would blame the fcups card. Because you are on the warranty, they will send you new boards. It is easy to replace them, no soldering, unless they send boards with caps too big to fit.....like the ones my friend got.
In his amp the fault was quite difficult to find, my friend had to send the amp to Hongkong. The potted output transformer by Silk was the blame. Inside the pot the transformer fell on the chassis and made a short. So they fixed it and sent it back. Unfortunately they did not notice, that the Mosfet on the supply board had been destroyed again, so he got another board again.
Turn you amp upside down and listen, if the output transformer
moves inside the pot.
regards
Andre

 

[ThorstenL]

Hi,

Thanks for your response. I did remove all tubes and the fuse still blows.

Does it make a difference if I only remove the rectifer and the 300b and leave the driver tubes.

If the Fuse still blows without tubes it means the tubes are not to blame.

The next stop would be to open up the Amp's and to disconnect the windings. It is possible your mains transformer is bad...

Do take it directly to diyhifisupply.

Ciao T

 

[anka58]

I have some relatively new Lux91 Mono Blocks (arrived in March). The amps have been fantastic until yesterday when one channel cut-out. I checked the fuse and it had blown. I have since replaced the fuse a couple of times and it immediately blows when the switch is turned on. I removed all tubes and inserted a new fuse and it still blows every time I turn the amp on. I have visually inspected the internals and nothing looks to be out of the ordinary. Can anyone walk me through some quick checks /diagnostics to isolate the problem.

Any help would be greatly appreciated.

Thanks

Hi

I had also problems with the fuse that blowed every 3-6 on-off turn.
I am in swiss, and here the LUX91 need 2 A 250V fuse. Originally there was a 1A 250V fuse, therefore it had to blow. Here we have 230-50. When you have 110-60 you need 3A fuse. You can read online in the LUX 91 manual.

I hope for you that you only need the right fuse.

 

[Chromene]

Thank-you very much for your reply. Unfortunately, I had already thought of this issue and it has the properly specified fuses.

My issue seems to run a bit deeper.

CD

 

[simsalabim]

To raise a topic from long ago, as i have a question regarding this amplifier i just bought second hand.

In my amps there were 3A fuses of the fast blow type.
I am in EU, from above post i understand that i need an 2A version, question i have is the following:

Can i safely use 2A slow blow fuses, as i have a pair in stock of the 'snake oil audio grade type' i like to use lol.

So can i use slow blow instead of fast blow?

The pdf of the lux91 manual is on the diyhifi website but it doesn't state which fuse to use anywhere.

Thank you on beforehand with any help, and please lets stay clear of discussion whether a fuse for audio is snake oil or not, just can i use slow instead of fast blow.

 

[Bas Horneman]

I always use 2A slow blow in my amps.