Looking for Avalon schems (VT-737SP)

[Apache5]

A friend have an Avalon VT-737SP out of garanty and it fuse burns when he puts on. I can repair it but I must have the schems and I cant find it ... Can someone know where I can try to find it? its possible to find it in internet?...

well, thanks all.

Arnau

 

[tony dB]

if you try to get in touch with Avalondistributors (or better exdistributors :grin: ) all over the EU i'm sure sooner or later there will be a nice soul helping you/us out!

Avalon self seems to be VERY protective about there schematics, as i read somewhere that they rather replaced a complete PCB then handing over the schematics... :shock:

Hope this lead to a solution for you.

If it's just meant to be a repairjob, i think there's enough qualified people overhere who could help you out too.

Cheers,

Tony

 

[tony dB]

just tried one of my own sources but even them as professional repair for a lot of topbrand audioequipment don't have acces to this. The person i spoke too is sure that he can repair it no matter what i would be, meaning you have to send it over to Belgium.
in case everything else fails pm me and i bring you in touch with this person and his company.

 

[Apache5]

Thanks Tony! we will try to contact with some distrubutor... Thanks too for your help offer :grin:

Arnau

 

[tony dB]

anytime, :grin:

i learn(ed) here a lot and gotten a pile of help (for free!), why shouldn't i try to help others with things i can have acces too?
Unfortunately this is not yet a very good knowledge of electronics but we're getting there bit by bit

that's DIY-spirit to me :thumb:

 

[philsaudio]

I opened up one the other day to find that the fine product engineers at Avalon obscured the part markings on all of the IC's in the box to assure a most difficult job repairing their faulty products. My opinion of people who do stuff like that is very very low. So low I would boycot their products no matter how they sound and who uses them.

 

[pucho812]

I opened up one the other day to find that the fine product engineers at Avalon obscured the part markings on all of the IC's in the box to assure a most difficult job repairing their faulty products. My opinion of people who do stuff like that is very very low. So low I would boycot their products no matter how they sound and who uses them.

I worked there as head of service, they do not  obscure the part markings for any IC, they also do not file them off or anything of the sort.  If you happen to have a unit that is like that it did not come from the factory that way.  they also have some of the best technical service around,  While they will not hand out schematics, they will spell it out for you so that any decent service tech  can work on them fairly easily and get it back to working.
about the only obscure markings is on the SMT parts which is due to the SMT part and not Avalon's doing.  From memory,  If your curious about the ic's the most common found is an lf412 used for DC offset for each discrete section, you will also find the occasional tl071 and opo7 for driving the VU meters.    There are others but  I can't recall them off hand.

As for the OP, if the unit is burning fuses, start by disconnecting the power supply from the unit and see if it powers up. My guess that it will not., then try it again with the power transformer disconnected from the power supply. if  the fuses does not pop with the power transformer, then you are good to go and it is not shorted.  reconnect the power supply and run it on a variac. You should see the current increase and continue to increase until the fuse pops as you increase the mains voltage till working.  if you do that, stick your finger on the rectifiers, one or more will be too hot to touch and that would be faulty. The most common issue to cause that is a failed KBU6D which is the bridge rectifier for the 6V supply line feeding the tubes. I would also replace c23 while there as that may also be shorted. either way the rectifier has an issue and needs replacement as it is the most common scenario as to why it's popping fuses.