UK Vintage Radio Repair and Restoration Powered By Google Custom Search Vintage Radio Service Data

Go Back   UK Vintage Radio Repair and Restoration Discussion Forum > Offered and Wanted Messages > Sets, Parts and Service Information Wanted (private buyers only, no swaps)

Notices

Sets, Parts and Service Information Wanted (private buyers only, no swaps) If you need help obtaining components, sets or equipment, post a message here. Private buyers only - no traders. No swaps.

Reply
 
Thread Tools
Old 15th Oct 2020, 7:20 pm   #1
chroma04
Pentode
 
chroma04's Avatar
 
Join Date: Jul 2008
Location: Doncaster, South Yorkshire, UK.
Posts: 101
Default Tuner required for Hitachi CNP-192

Hi,

Does anybody happen to have a working tuner for the Hitachi CNP-192 colour television which they'd be willing to part with? I believe the set dates from around 1974?

The symptoms are a weak, grainy picture, with just a blank white (snow-less) raster with the aerial removed.

All costs met, of course!

Adrian.
Attached Thumbnails
Click image for larger version

Name:	DSC02398.jpg
Views:	89
Size:	52.5 KB
ID:	217990   Click image for larger version

Name:	DSC02378.jpg
Views:	84
Size:	89.4 KB
ID:	217991   Click image for larger version

Name:	DSC02381.jpg
Views:	81
Size:	71.9 KB
ID:	217992  
__________________
Chroma 04
chroma04 is offline   Reply With Quote
Old 15th Oct 2020, 7:51 pm   #2
HamishBoxer
Dekatron
 
HamishBoxer's Avatar
 
Join Date: Aug 2007
Location: W.Butterwick, near Doncaster UK.
Posts: 7,561
Default Re: Tuner required for Hitachi CNP-192

Have you tried opening up the tuner and looking for drys on the earthing bushes?
__________________
G8JET BVWS Member and V.M.A.R.S
HamishBoxer is offline   Reply With Quote
Old 15th Oct 2020, 8:14 pm   #3
chroma04
Pentode
 
chroma04's Avatar
 
Join Date: Jul 2008
Location: Doncaster, South Yorkshire, UK.
Posts: 101
Default Re: Tuner required for Hitachi CNP-192

Thanks for the reply HamishBoxer,

I must admit I haven't opened the unit up, but I will have a look. Thanks for the tip!

Adrian.
__________________
Chroma 04
chroma04 is offline   Reply With Quote
Old 15th Oct 2020, 10:31 pm   #4
Nuvistor
Dekatron
 
Nuvistor's Avatar
 
Join Date: Aug 2013
Location: Wigan, Greater Manchester, UK.
Posts: 8,056
Default Re: Tuner required for Hitachi CNP-192

They did suffer from bad joints etc, it’s a varicap tuner if I remember correctly.
__________________
Frank
Nuvistor is offline   Reply With Quote
Old 16th Oct 2020, 3:58 pm   #5
G6ONEDave
Hexode
 
Join Date: Dec 2019
Location: Owston Ferry, North Lincolnshire, UK.
Posts: 366
Default Re: Tuner required for Hitachi CNP-192

Also check that you have the 33v varicap tuning supply, as well as the 12v supply, possibly there might be 2 of the 12v supplies to the tuner can. Circuits are available if you don't already have one.
Dave
G6ONEDave is offline   Reply With Quote
Old 16th Oct 2020, 5:37 pm   #6
chroma04
Pentode
 
chroma04's Avatar
 
Join Date: Jul 2008
Location: Doncaster, South Yorkshire, UK.
Posts: 101
Default Re: Tuner required for Hitachi CNP-192

Thanks for the head's-up on the 33v tuning voltage. It is present, and does vary accordingly, when tuning through the band.

Since there was nothing to lose, I opened up the tuner unit and I think I may have discovered the issue. The 2SC535 transistor in the mixer stage is o/c Base/Emitter. I will have a look for a suitable device - it's worth a shot!

Adrian.
Attached Thumbnails
Click image for larger version

Name:	DSC02401.jpg
Views:	50
Size:	64.2 KB
ID:	218056  
__________________
Chroma 04
chroma04 is offline   Reply With Quote
Old 18th Oct 2020, 7:09 pm   #7
vinrads
Nonode
 
Join Date: Feb 2009
Location: Chesterfield, Derbyshire, UK.
Posts: 2,383
Default Re: Tuner required for Hitachi CNP-192

Nice one ,hope it cures it , this is the set you could take to the customer in it's box and guarantee it would work , after a long reliable service the crt would go soft focus , how is yours . Mick.
vinrads is offline   Reply With Quote
Old 19th Oct 2020, 9:34 am   #8
chroma04
Pentode
 
chroma04's Avatar
 
Join Date: Jul 2008
Location: Doncaster, South Yorkshire, UK.
Posts: 101
Default Re: Tuner required for Hitachi CNP-192

The focus actually doesn't appear too bad, though it's hard to know for sure at this stage as I have yet to see a good signal on the set with the signal generator connected. I have noticed slight mis-convergence toward the lower edges of the picture, but I may leave this alone, as I'm no expert in this area and I may well make matters worse...

To be honest, my main concern was whether there would be any life at all in the CRT, due to the set employing the 'Instant Picture' feature, whereby the set can be left in standby, with the CRT heaters alight, but the set otherwise unpowered. However from what I can see it's a fairly bright picture.

I have a 2SC535 transistor on order, which should be here by the end of the week. Fingers crossed this sorts it!

Adrian.
__________________
Chroma 04
chroma04 is offline   Reply With Quote
Old 20th Oct 2020, 4:59 pm   #9
chroma04
Pentode
 
chroma04's Avatar
 
Join Date: Jul 2008
Location: Doncaster, South Yorkshire, UK.
Posts: 101
Default Re: Tuner required for Hitachi CNP-192

Just to conclude this thread. The transistor arrived today and fitting it has restored correct operation to the tuner. And in colour too!!

There are still a couple of issues to sort out (lack of height and intermittent push-buttons), but I'm hopefully on the home straight now.

Thanks to everyone who replied.



Adrian.
Attached Thumbnails
Click image for larger version

Name:	DSC02438.jpg
Views:	23
Size:	35.3 KB
ID:	218441  
__________________
Chroma 04
chroma04 is offline   Reply With Quote
Reply

Thread Tools



All times are GMT +1. The time now is 12:50 am.


All information and advice on this forum is subject to the WARNING AND DISCLAIMER located at https://www.vintage-radio.net/rules.html.
Failure to heed this warning may result in death or serious injury to yourself and/or others.


Powered by vBulletin®
Copyright ©2000 - 2020, vBulletin Solutions, Inc.
Copyright ©2002 - 2020, Paul Stenning.