electronics, repairs, service manuals and datasheets discussion community for the repairs professionals and technicians
FAQSearchMembersGroupsRegisterProfilePM'sLogin/Out
Sony VCR misteriously back to life

 
Post new topic   This topic is locked: you cannot edit posts or make replies.    Electronic equipment repair and service manual search discussion Forum Index -> Equipment Repairs
View previous topic :: View next topic  
Author Message
jestick



Joined: 31 Aug 2005
Posts: 3

PostPosted: Wed Aug 31, 2005 9:10 pm    Post subject: Sony VCR misteriously back to life Reply with quote

Hello everyone, I'm new to this forum, it seems very nice!
I have a question about a sony vcr slv-se70. The unit went dead after a storm . I opened it and checked for fuse fault or broken components, but all seemed right. So I went on checking the voltage outputs on the secondary part of power supply (points and values to be found are printed on the board itself) and all read zero: I tought it was a power supply failure so went on trying to find the problem until at one moment I touched with the com tip a joint of a diode, and suddendly it pops a spark. I jumped and switch off power, take a deep breath, then came back to work and *magic*: the vcr power up, I reassembled it and it's now perfectly working. Only notice is a little 'fizz' from the power supply at power on.
So here comes the question(s): what can be happened? Is the unit safe? Is there any test to make for safety?
Thanks to everyone, sorry for the long post (and bad english), but I'm a bit scared there could be a lurking problem.

Regards
Jestick
Back to top
View user's profile Send private message
gary



Joined: 05 Apr 2005
Posts: 584
Location: MANCHESTER, uk

PostPosted: Thu Sep 01, 2005 5:57 am    Post subject: Reply with quote

on the small sub board in the psu replace the small electrolytic capacitors as they have fallen in value, the soldering iron will have helped start the psu with a spike and once it is running the caps value will gradually rise as they warm up which is why it now runs ok and will unless unplugged for an hour
Back to top
View user's profile Send private message
jestick



Joined: 31 Aug 2005
Posts: 3

PostPosted: Thu Sep 01, 2005 8:44 am    Post subject: Reply with quote

Didn't thought about that, it really make sense!
Thank you for the advice, I'll replace those caps ASAP.
Back to top
View user's profile Send private message
petert



Joined: 05 Sep 2005
Posts: 5

PostPosted: Mon Sep 05, 2005 10:12 am    Post subject: Reply with quote

Hi, i own the same model.
I have a psu problem that im solving right now.
I found that one of the two big diodes on the sub psu box are faulty.
I replace it and seems to works so far.
I saw outside of that aluminum box that the two big resistors 33Ω/3W & 180Ω/2W is very hot and with the regulator beside them have burn out the board around them.
I purchase some biger resistor and a good heatsink for the regulator to relieve the hot environment on that spot.

You think that is necessary to change some capasitors generaly on the psu? I know that heat dosnt make good to those things.
Back to top
View user's profile Send private message MSN Messenger
Guest






PostPosted: Wed Sep 07, 2005 4:46 am    Post subject: Reply with quote

So, the vcr seems to work fine.
I changed the resistors with 5W and plased a nice heatsink on the regulator. Temperature around them is fine now.

I solved also a problem with the lift and everything works fine.

If someone wants the schematic, he can send me a notice
Back to top
petert



Joined: 05 Sep 2005
Posts: 5

PostPosted: Wed Sep 07, 2005 4:48 am    Post subject: Reply with quote

The guest above is me, Petert
Back to top
View user's profile Send private message MSN Messenger
jestick



Joined: 31 Aug 2005
Posts: 3

PostPosted: Wed Sep 07, 2005 4:50 am    Post subject: Reply with quote

Hi Petert, I couldn't work on the vcr on the past week, so it's on the same conditions as it was on my first post. My psu seems in good conditions, no burn spots or overheating components, but I have to control more carefully. You managed to open the aluminium box? It seems that it has to be cutten, am I right?
Back to top
View user's profile Send private message
petert



Joined: 05 Sep 2005
Posts: 5

PostPosted: Wed Sep 07, 2005 5:10 am    Post subject: Reply with quote

Its easy to open that box.
You must unsolder the 5-6 foots of the box at the bottom of the board.
Then unsolder the pins and there it is.
After that you can open it easyly.

In the middle of testing, i solder only the board (without the alum box) on the main psu by very little solder, just to see if it works. After testing, i was close it again and solder it once for all.
Back to top
View user's profile Send private message MSN Messenger
petert



Joined: 05 Sep 2005
Posts: 5

PostPosted: Wed Sep 07, 2005 5:16 am    Post subject: Reply with quote

That "fizz" that you mentioned on your first post, is happened to me too
Back to top
View user's profile Send private message MSN Messenger
petert



Joined: 05 Sep 2005
Posts: 5

PostPosted: Wed Sep 07, 2005 5:27 am    Post subject: Reply with quote

Chek this out

CN600 pin 4 --> 35.0 to 41.0 V
CN600 pin 5,6 --> 12.5 to 14.5V
IC601 pin 2 -->11.0 to 13.0 V
CN600 pin 14 5.40 to 6.40V
CN600 pin 2.3 --> 4.7 to 5.7V
CN600 pin 7,8 --> 12.5 to 14.5V
D603 at cathode --> 4.5 to 5.5V
CN600 pin 16,19 --> 1.9 to 3.9V (Between 16 and 19) (16 must be + and 19 the -)
CN600 pin 18 --> -12.5 to -10.5V
Back to top
View user's profile Send private message MSN Messenger
Display posts from previous:   
Post new topic   This topic is locked: you cannot edit posts or make replies.    Electronic equipment repair and service manual search discussion Forum Index -> Equipment Repairs All times are GMT
Page 1 of 1

 
Jump to:  
You can post new topics in this forum
You can reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum


Електроника София - Service Manuals Free Download - Prikachi - Service Diagrams

Free TV Schematics Download - HARDW.net - Pinout Master - Jabse Search - Jabse.InK  - Pulsator

Connector Pinout Forum - Новини - SnimkiOt.com - безплатен DNS - Whois разузнаване - Poblizo.com : пътешествия