Welcome to Australia's only Vintage Radio and Television discussion forums. You are not logged in. Please log in below, apply for an account or retrieve your password.
Australian Vintage Radio Forums
  Home  ·  About Us  ·  Discussion Forums  ·  Glossary  ·  Outside Links  ·  Policies  ·  Services Directory  ·  Safety Warnings  ·  Tutorials

Tech Talk

Forum home - Go back to Tech talk

 HMV C23C Table radio multi band
« Back · 1 · 2 · Next »
 Return to top of page · Post #: 1 · Written at 1:04:43 PM on 29 June 2020.
Jimb's Gravatar
 Location: Kanahooka, NSW
 Member since 18 November 2016
 Member #: 2012
 Postcount: 659

Hi all does anyone have a dial cord string diagram for this radio. I have the circuit information but not the stringing diagram.
I must be an idiot taking on this radio it is a dirty horrible radio. It is another Good Samaritan project for this guy who inherited his Dad's house full of old electronics. I gave him back his repaired STC A141 chassis yesterday and I got stuck with this. At this stage I am providing my labour free of charge because I need to keep constructively occupied it saves me buying radios I do not need, and can't afford anyway. There are components hanging in festoons from the underside of chassis . I left the case with him because I do not want to risk dropping and busting it. One of the major problems is it has a lot of screened perished rubber wiring that I will need to try and replace. Or should I leave it undisturbed and hope for the best?
I have removed the speaker and baffle the plastic surround looks absolutely gross it is now in the dishwasher. If it comes out melted and buckled my troubles will be over.I will just take it back to him in a box and say sorry.
Regards Jimb


 
 Return to top of page · Post #: 2 · Written at 2:10:32 PM on 29 June 2020.
MonochromeTV's avatar
 Location: Melbourne, VIC
 Member since 20 September 2011
 Member #: 1009
 Postcount: 1133

Give this a go:

https://www.kevinchant.com/uploads/7/1/0/8/7108231/chassis_type_42.pdf

According to Radiomuseum C23C & 42-71 are the same.


 
 Return to top of page · Post #: 3 · Written at 3:10:27 PM on 29 June 2020.
Jimb's Gravatar
 Location: Kanahooka, NSW
 Member since 18 November 2016
 Member #: 2012
 Postcount: 659

Thanks Monochrome I will try it out.


 
 Return to top of page · Post #: 4 · Written at 5:27:51 PM on 29 June 2020.
Jimb's Gravatar
 Location: Kanahooka, NSW
 Member since 18 November 2016
 Member #: 2012
 Postcount: 659

Thank you Monochrome TV. I now have a full workshop manual thank you so much.
Well the front panel survived the dishwasher .The HMV badge came up pretty good the speaker cloth parted company ,it was filthy anyway.It is now clean however it is pretty frayed not sure if I can salvage it. However I will just find something else In its place if I can't salvage it I am sure I can find an old pair of underpants with crook elastic I can cut up. Off white would be ok what do you think??
I am very greatfull for you forum members always ready to help, at times I feel a bit of a bludger I have not contributed much of use to these forums if I have anything of value to contribute I will , however my experience and knowledge is way under you guys, just letting you know I do appreciate your help.
Kind Regards as always Jimb


 
 Return to top of page · Post #: 5 · Written at 5:42:16 PM on 29 June 2020.
Vintage Pete's avatar
 Location: Albury, NSW
 Member since 1 May 2016
 Member #: 1919
 Postcount: 1993

Jim,
See if ya can pop a pic of the grill cloth you need..

Pete


 
 Return to top of page · Post #: 6 · Written at 7:29:01 PM on 29 June 2020.
Jimb's Gravatar
 Location: Kanahooka, NSW
 Member since 18 November 2016
 Member #: 2012
 Postcount: 659

Hi Pete.
I will take a photo tomorrow in Good light.
Regards Jimb.


 
 Return to top of page · Post #: 7 · Written at 9:47:53 AM on 1 July 2020.
Jimb's Gravatar
 Location: Kanahooka, NSW
 Member since 18 November 2016
 Member #: 2012
 Postcount: 659

Hi all,can someone please tell me what colour the speaker surround panel ( main front panel ) of this HMVC23C table radio should be.
In spite of my best efforts to clean it still looks like rubbish. I have looked at images on the net and some of them look like rubbish also.
I think they were painted maybe cream. I think the problem is some of the paint has chipped off and there are areas of white while some is a dirty brown colour. Because the panel is now stripped bare I would like to give it a spray.
Your advice as always will be appreciated.
Regards Jim


 
 Return to top of page · Post #: 8 · Written at 9:56:41 AM on 2 July 2020.
Jimb's Gravatar
 Location: Kanahooka, NSW
 Member since 18 November 2016
 Member #: 2012
 Postcount: 659

Hi all.
Well I have the chassis up and running , still a long way from completed . I have to fit the speaker and surround after finding a suitable colour to paint it and the worst job of all which I hate will be trying to restring the dial cord after refitting the dial.
The chassis is quite good to work on being large and plenty of space under there it also has a roll cage of sorts metal hoops both ends which the speaker surround and case bolt to it makes it good to roll around upside down to work on.
If the dial cord had been in place and working I would not have disturbed it, although it was so deplorably filthy it made it easier to clean without the dial and surround in place.
Regards Jimb.


 
 Return to top of page · Post #: 9 · Written at 10:40:00 AM on 2 July 2020.
Vintage Pete's avatar
 Location: Albury, NSW
 Member since 1 May 2016
 Member #: 1919
 Postcount: 1993

Yes, Dial string, I'm really bad at it!
I've only done it a couple of times and I find it really hard to get right .

Pete


 
 Return to top of page · Post #: 10 · Written at 10:44:15 AM on 2 July 2020.
Ian Robertson's Gravatar
 Location: Belrose, NSW
 Member since 31 December 2015
 Member #: 1844
 Postcount: 1905

I have a method I use for working it out. It's complicated so I'll have to write it up.

But the main tricks are that the scale string run moves in the right direction and that a tangent tp the drum is possible on both entry-exit to the drum at both extremes of the gang.


 
 Return to top of page · Post #: 11 · Written at 11:46:28 AM on 2 July 2020.
Jimb's Gravatar
 Location: Kanahooka, NSW
 Member since 18 November 2016
 Member #: 2012
 Postcount: 659

Hi Pete and Ian.
I may be able to salvage the existing cord it became detached from the dial pointer maybe due to tightness in the shafts and the gang itself. It is partly still around the pulley.
Regards Jimb


 
 Return to top of page · Post #: 12 · Written at 2:06:37 PM on 2 July 2020.
Ian Robertson's Gravatar
 Location: Belrose, NSW
 Member since 31 December 2015
 Member #: 1844
 Postcount: 1905

Generally speaking you'll need to give up on the existing cord. Mostly they are cotton and will snap when you try to refit them, or soon after.

Nylon dial cord is still available and it does a permanent job. But with nylon you need to be especially careful to keep oil away from it. Once even the slightest trace of oil gets on the drive pulley you will never stop it slipping. It'll be a case of washing everything down thoroughly and doing it all again with new cord.


 
 Return to top of page · Post #: 13 · Written at 5:58:18 PM on 2 July 2020.
Jimb's Gravatar
 Location: Kanahooka, NSW
 Member since 18 November 2016
 Member #: 2012
 Postcount: 659

Hi Ian .
I understand what you are saying however cowardice has overtaken me I managed to get the old cord restrung and it appears to be working ok.I am just not brave enough to attemp replacement.I actually not sure if I took this off I could restring it.
So basically I have resprayed the front panel and it came out pretty good. Chassis wise it is all back together and working, however if the volume is cranked up it goes into distortion. Using a standard 20,000 ohm per volt multimeter which I am assuming was used at the time the voltages and resistances to ground appear to be ok. I thought I would find some discrepancies around the 6M5 but no,it looks normal to me. Is it a case of the Miserable little 5 inch speaker being driven too hard? Have no idea why such a large radio would have been sent out the factory with such a crappy Little speaker . Thoughts please everyone?
Ian I need to ring you some time if that is ok? In regards to the TRF radio.
Kind Regards Jimb.


 
 Return to top of page · Post #: 14 · Written at 8:39:51 PM on 2 July 2020.
Ian Robertson's Gravatar
 Location: Belrose, NSW
 Member since 31 December 2015
 Member #: 1844
 Postcount: 1905

Sure Jim call any time.

Could just be the speaker. Are you running it out of the cabinet?
Could be lots of things. What is the voltage between G1 and cathode of the 6M5?


 
 Return to top of page · Post #: 15 · Written at 8:57:23 PM on 2 July 2020.
Jimb's Gravatar
 Location: Kanahooka, NSW
 Member since 18 November 2016
 Member #: 2012
 Postcount: 659

Ian the speaker is mounted back in its place. The bias on grid 1 is minus 1.4 volts in respect to the cathode which is grounded.
Regards Jim.


 
« Back · 1 · 2 · Next »
 You need to be a member to post comments on this forum.

Sign In

Username:
Password:
 Keep me logged in.
Do not tick box on a computer with public access.