electronics, repairs, service manuals and datasheets discussion community for the repairs professionals and technicians
FAQSearchMembersGroupsRegisterProfilePM'sLogin/Out
Toshiba 865B VCR digital auto & manual tracking ineffect
Goto page 1, 2  Next
 
Post new topic   Reply to topic    Electronic equipment repair and service manual search discussion Forum Index -> Equipment Repairs
View previous topic :: View next topic  
Author Message
DaveH
Guest





PostPosted: Thu Dec 29, 2005 8:40 pm    Post subject: Toshiba 865B VCR digital auto & manual tracking ineffect Reply with quote

The tracking adjustment is normally relatively ineffective - with 'sparking' noise along lower part of picture. Manual adjust has some effect but does not fully remove the noise

The problem is present when playing all tapes, including pre-recorded.

Curiously the problem comes and goes, after a long period with the problem the vcr was recently moved and reconnected and the problem disappeared. When the vcr was moved to a more convenient location the and reconnected the problem returned.

Any advice will be much appreciated.

Regards

DaveH
Back to top
Al_Dodge_Bundy



Joined: 05 Apr 2005
Posts: 93
Location: Netherlands

PostPosted: Fri Dec 30, 2005 10:18 pm    Post subject: Reply with quote

First be sure the videoheads are cleaned properly (not just with a cleaning tape), and the rubber idler roller is clean and not dried out!

Also check the v-belts (if available).

Grtz Mark
Back to top
View user's profile Send private message
Guest






PostPosted: Sat Dec 31, 2005 5:55 pm    Post subject: Reply with quote

Grtz Mark

Thanks for your prompt reply.

The video heads were cleaned with chamois cleaner pads and head cleaner solution so should be OK but I will double check. The rubber idler roller seemed clean - but I will reinspect to see if it has hardened.

I shall also take the opportunity to clean and lubricate the cam tracks which govern head and guide post movements.

Any further advice would be welcome

Regards

DaveH
Back to top
sparky



Joined: 18 Nov 2005
Posts: 98
Location: U.K

PostPosted: Sun Jan 01, 2006 8:21 am    Post subject: Toshiba 865B VCR digital auto & manual tracking ineffect Reply with quote

Ensure correct movement of tape (not riding up and down on the control head or entry/exit guides) and the entry/exit guides are going fully home in the play mode. If o.k then try head switching point adjustment.

Happy New Year
_________________
If in doubt pull the plug out.
Back to top
View user's profile Send private message
Guest






PostPosted: Mon Jan 02, 2006 9:17 pm    Post subject: Reply with quote

Grtz Mark, Sparky


I have had a careful look at the inside of the VCR and I am puzzled by the Head Cleaner at the rear of the Cylinder Assembly.

The Head Cleaner Roller Sub-Assembly seems to consist of a simple white U-shaped hard-plastic bobbin that never makes contact with the Head

Is this the roller sub assembly, or has something been left off when the VCR was last serviced by Toshiba ?

Regards

David H.
Back to top
Al_Dodge_Bundy



Joined: 05 Apr 2005
Posts: 93
Location: Netherlands

PostPosted: Mon Jan 02, 2006 10:37 pm    Post subject: Reply with quote

The head cleaner roller, should make contact with the video head, whenever you eject a tape (or push the cleaning button on your VCR (if available) for a short time.

But if you already cleaned the heads properly, a none functioning head cleaner, will not be your problem.
Back to top
View user's profile Send private message
sparky



Joined: 18 Nov 2005
Posts: 98
Location: U.K

PostPosted: Tue Jan 03, 2006 1:03 am    Post subject: Toshiba 865B VCR digital auto & manual tracking ineffect Reply with quote

The head cleaner roller normally has a spong attached to the plastic roller that can become dirty and cause more harm than good by actually making the heads dirty. I would have thought Toshiba would have replaced it though.
_________________
If in doubt pull the plug out.
Back to top
View user's profile Send private message
Guest






PostPosted: Tue Jan 03, 2006 1:38 am    Post subject: Reply with quote

Grtz Mark, Sparky

Thanks for your help.

No sign of the head cleaner sponge roller - the Toshiba service agent must have concluded that its more trouble than its worth, or simply been out of stock etc.

Heads guide posts, tension posts, idle rollers etc cleaned, plus load / reload tracks for guide and tension pins cleaned and lubricated.

A couple of worrying moments when it unwound (and ruined) a cassette into the head area durign a load, but after extracating the casette power-lead removal reset the load cam OK.

VCR now works noise free (with the lid off) with auto track correcting system working properly at last.

Curiously playback noise levels are significantly higher with the case lid replaced. All earth tags etc cleaned but I cant locate the exact cause. Guess its an earth loop problem or similar.

Regards

DaveH.
Back to top
sparky



Joined: 18 Nov 2005
Posts: 98
Location: U.K

PostPosted: Tue Jan 03, 2006 3:52 am    Post subject: Toshiba 865B VCR digital auto & manual tracking ineffect Reply with quote

Trying to remember the deck used in this machine as been out of the trade a few years now (memory going a signe of old age) but seem to recall a small bracket that was fitted between the chassis and pcb that was too short and Toshiba supplied a longer one as a modification to improve the earthing. The symptoms were white noise dots on playback.
If I didn't have a bracket I tinned the copper part on the pcb and soldered.
Another part that caused noise problems was electrolytic capacitor C051 1uF, 50V on the lower drum pcb leaking and eating away the print. The cure was to remove, repair the print and replace the capacitor (I just used a miniture 105 degree type). Also have a look at the capstan pulley ensuring it does not have a split. If it was split I Removed and fitted a metal one supplied for Mitsubishi with a little glue.
The drum may have a bit of friction if it mangled a tape on rewind but if it becomes a problem you could polish it with brasso while being careful not to clog the heads.
This is purely memory so it may be poss I may be getting confused with another as you can appreciate the amount of makes and models of equipment a service department obtain for repair.
I still have quite a few spare parts and may have this bracket but remember ordering several and obtaining the original type instead which was of little use. A lack of communication between Toshiba spares and technical department perhaps.
_________________
If in doubt pull the plug out.
Back to top
View user's profile Send private message
sparky



Joined: 18 Nov 2005
Posts: 98
Location: U.K

PostPosted: Tue Jan 03, 2006 3:58 am    Post subject: Toshiba 865B VCR digital auto & manual tracking ineffect Reply with quote

This bracket was fitted at the rear of the drum assembly.
_________________
If in doubt pull the plug out.
Back to top
View user's profile Send private message
Display posts from previous:   
Post new topic   Reply to topic    Electronic equipment repair and service manual search discussion Forum Index -> Equipment Repairs All times are GMT
Goto page 1, 2  Next
Page 1 of 2

 
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