JVC CA-UXP55 HIFI Problem

Cheers Billy

snipped-for-privacy@googlegroups.com... Hi, This unit failed to= power up. Removed case and found the internal 1amp slow blow fuse (T1AL) w= as shot. replaced fuse turned power on power to unit successful as unit goe= s into standby mode red light on front and clock displayed. As soon as the = unit is turned on proper the Fuse blows again. I am a novice at this sort o= f thing but did some rudimentary checking on the board that the transformer= is attached to looking for blown capacitors or a short of some kind, can a= nyone suggest a way forward. I am thinking it cannot be that much wrong wit= h it as initail power up is ok? I would rather attempt a repair than put it= into a shop as the cost of repair would probaly outweigh the value of the = unit. any help? suggestions? Cheers Billy ++++++ Checked the speaker wiring= ? What is the output device/s ?

didn't have the speakers connected. heres a link to give you an idea of the unit in question

Oh how I wish I had a quid for every time that I've heard that. It's a bit like saying that you have a pain in the chest, but you're sure it can't be much because you've had pains in your arms or legs before, and they haven't been anything serious ...

Chances are that in standby, very little other than the system control micro is actually powered. When you attempt to take it out of standby, that's when the main rails to (for instance) the output stages will come up. Any short across any of the main rails, will likely take the fuse out. By far the most common reason for such a short to be present, is failed output devices. these might be in the form of discrete transistors, or integrated into a car radio-type output IC, or an STK output hybrid. Without schematics, you may not find that you can progress very far, given your admitted lack of experience ...

Hmmmm ... d:-\ }=

Arfa

thanks for the reply have taken unit apart to investigate further cannot see any obvious short the small board seems basic (says i the novice so please excuse my ignorance )

i will try and post a few pictures if it may help maybe the sages on this site can nurse me through a little more investigation?

It's not really a 'site' as such. It's a usenet newsgroup that is being fronted by the Google Groups site that you are accessing from. You probably won't be able to post pictures direct. Most people post a link to something like Photo Bucket, where they place the pictures.

Arfa

snipped-for-privacy@googlegroups.com... > i will try and post= a few pictures if it may help maybe the sages on this > site can nurse me = through a little more investigation? > It's not really a 'site' as such. It= 's a usenet newsgroup that is being fronted by the Google Groups site that = you are accessing from. You probably won't be able to post pictures direct.= Most people post a link to something like Photo Bucket, where they place t= he pictures. Arfa

links to pictures....

thanks for looking... the blown fuse is in top left of the board mains inpu= t goes into the socket near it. tips on how to try and trace the fault would be good, is the board relative= ly simple?=20

Cheers Billy

Billy, those photobucket links don't seem to work.

Gareth.

re try of the photo links!

p slow blow fuse (T1AL) was shot. replaced fuse turned power on power to un= it successful as unit goes into standby mode red light on front and clock d= isplayed. As soon as the unit is turned on proper the Fuse blows again. I a= m a novice at this sort of thing but did some rudimentary checking on the b= oard that the transformer is attached to looking for blown capacitors or a = short of some kind, can anyone suggest a way forward. I am thinking it cann= ot be that much wrong with it as initail power up is ok? I would rather att= empt a repair than put it into a shop as the cost of repair would probaly o= utweigh the value of the unit. any help? suggestions? Cheers Billy

Thanks for your help and the pointers re the fuse. I havent had time to look again but will over the weekend, looking like a r= eplacement transformer But probably not worth the cost. Thanks you very much for your help. You never know i may have something else thrown at me to fix and i may ask = for more help in the future. take care

Cheers Billy

On Wed, 12 Sep 2012 01:13:05 -0700 (PDT), Billy Brainstorm put finger to keyboard and composed:

Direct links to your photos ...

Page 8 of the following UX-P5 circuit diagrams looks very much like your power supply board. The P/N of the main transformer is the same in any case.

UX-P5 Service Manual:

The following link looked promising, but it has expired:

Here is another service manual, but it looks quite a bit different:

- Franc Zabkar

Looking at the PSU schematics, it's *just* possible that one of the VH reccies - that's D1004 to D1007 - might take out the primary side fuse if it was short circuit. That said, the fuse did look very violently blown in the picture. Still, Billy, I guess before condemning the transformer, it would be worth just checking those diodes with an ohm meter, and the wires to points 1, 2, 3 & 4, 5, 6 disconnected.

Arfa