Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems.

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
  #1   Report Post  
 
Posts: n/a
Default toshiba m-651 vcr with noisy HI-FI

Hi all,

EET here doing some fun garage repair to add some stuff to my a/v
system. I picked up this Toshiba M-651 VCR at a second-hand store for
$20.00 (with the original remote!). This machine is built like a tank
(reminds me of my JVC HR-910U which is still going strong after two
belt replacements and replacing a bad electrolytic in the RF/IF
Stages.)

Anyway I brought this Toshiba home and started to assess the reason why
the sticker said "as-is". Everything works fine on this machine except
for the "popping/dro-outs" in HI-FI mode when playing a tape (doesn't
matter if it is pre-recorded or home recorded)(and the HI-FI output amp
works perfectly in TV mode) and the video is rock solid and clear
(which I understand is normal when During early stages of Video Head
wear because the HI-FI heads wear first since they protrude farther out
from the cylinder).

At this point I am starting to assume that the HI-FI heads are worn on
upper cylinder. But! I did do all of my "standard checks" listed below
first before deciding to type this topic up and verify my diagnosis
with "the more experienced" members of the repair group.

1. Checked and cleaned all belts (looks like they've been replaced
recently)

2. cleaned pinch roller and capstan post (not too bad but maybe in a
couple of years I would replace the pinch roller. the capstain post is
nice and snug (no sign of bearing wear).

3. cleaned Video and ACE Heads. No improvement in HI-FI sound.

4. I "gently tweaked" the ACE head for possible drift. ACE head drifts
out of HI-FI mode pretty uniformaly in all directional adjustments. So,
it seems "well centered". I know I should use a scope, but I have fixed
about 8 of these for friends who used the "well it really just like a
big cassette deck approach" and misaligned their machines. I use the
same ACE alignment method outlined in the Sci.Electronics VCR Repair
FAQ on ACE head adjustment without a scope.

5. Tweaked right and left guide posts (last resort that I know of
before assuming bad video heads). No improvement.

6. Downloaded the VCR Repair FAQ to make sure I did everything I could
with the limited equipment I have. (Fluke meter, LC meter).

7. Checked Linear stereo mode and sound is clear and channel separation
is good.

So I humbly ask the more experienced if my conclusion is right and I
need to dump the $20.00 on a new video head from MCM?

Please understand that I have no problem putting $45.00 into this VCR
as I love the older "tank-built" VCRs and this toshiba would probably
cost $200.00 or more to buy new (if any body would make a good VCR like
this today...).

I also humbly wish to ask another dumb question since I have never done
a video head replacement before. That question is this:

When I order this part from MCM, will I be getting a new upper cylinder
with the video and HI-FI heads "built-in". Or will I be getting the
Heads that I will have to install into my existing upper cylinder and
then reinstall that onto the lower drum assembly. I know this might
seem like a dumb question, but the way the "terminology" and the "buzz
words" get thrown around in the books and on the net I can't seem to
get a clear picture regarding that.
Many thanks for anyone who will take the time to help.


John Z.

  #2   Report Post  
AshTray700
 
Posts: n/a
Default

maybe im not correct on this , but if you have a good picture , why are you
replacing the video head assy , arent the audio heads on the other side of
the tape path on a block rather than the big video disk?

  #3   Report Post  
davexnet02
 
Posts: n/a
Default

On Mon, 20 Dec 2004 11:53:29 -0500, "AshTray700"
wrote:

maybe im not correct on this , but if you have a good picture , why are you
replacing the video head assy , arent the audio heads on the other side of
the tape path on a block rather than the big video disk?

The linear (poorer) audio is, but the hifi audio is accessible via
heads on the rotating drum, just like the video.

Dave
Reply
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules

Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Question on Toshiba 20AF44 Don Allen Electronics Repair 1 July 3rd 04 04:42 AM
ICs for Sale - Specials, obsolete and Memory The Photographer Electronics Repair 0 June 3rd 04 11:40 PM
ICs for Sale - Specials, obsolete and Memory Kristy Electronics Repair 2 April 14th 04 04:24 AM
ATT; Hobbyists and Repairmen I have accumulated a room of ICS, Transistors, Diodes , Mem Chips , Proms etc Kristy Electronics Repair 1 December 8th 03 04:06 AM
Toshiba TP50H15 Dead David Electronics Repair 1 September 17th 03 09:52 PM


All times are GMT +1. The time now is 07:12 AM.

Powered by vBulletin® Copyright ©2000 - 2023, Jelsoft Enterprises Ltd.
Copyright 2004-2023 DIYbanter.
The comments are property of their posters.
 

About Us

"It's about DIY & home improvement"