Just curious if anyone has seen this type of arrangement of a resistor wound on a mica sheet (1.4 ohms) in series with the dial lamps....can only assume its there to lower voltage & extend the life of the panel lamps? I have not seen anything like it. Follow the link http://s860.photobucket.com/albums/ab167/pjfitzy/HMV%20881/ for a view.

Its in a HMV 881 circa 1941. even more oddly they used pin 6 of the 6v6 socket (unused) as a tag strip for the connection out to the lamps.

More importantly does anyone have any recommendations for cleaning the tuning gang of radios.
This one is gunk covered after living in a kitchen its entire life & I am eager to hear if anyone has had experience cleaning while the unit is still in the chassis if this is possible??

Paul

I was reading about cleaning tuning capacitors in one of the HRSA 'Radio Waves' issues a few weeks back but can't recall which one at the moment. I'll try to find it again.

Meanwhile, there's quite a bit on the web, ranging from using dishwashers (quite popular!), to chemicals like carbie cleaner and gun cleaner, to less dramatic methods, most of which involve removing the gang from the chassis:

http://www.vintage-radio.net/forum/showthread.php?t=39915.

http://www.radioremembered.org/tips.htm#ctc.

http://www.antiqueradios.com/forums/viewtopic.php?t=109261&view=next&sid=635a1ad560de0b6b468e5ebb845d9b39.

I recommend 'dry cleaning' for the tuning condenser. Use kerosene rather than petrol as it is less explosive. Be mindful of the fact that it is still smelly though so doing any of this type of cleaning outside is recommended.

There is a chance however that you won't get away from having to remove the condenser from the chassis and this isn't such a bad thing as it provides an opportunity to clean underneath where the condenser is fitted and this improves presentation of the chassis once the restoration project is complete.

I would lubricate the bearings/bushes of the condenser with silicon spray rather than grease or oil. Silicon spray doesn't attract dust and dirt the way oil-based lubricants do.

Resistors in series with dial lamps were in most cases there to either allow the use of 6 volt lamps (it may have been retrofitted) or fitted by the manufacturer to stop 6.3 volt lamps dying when the mains voltage fluctuated. The electricity supply would not have been as stable in 1941 as it is today.

This HMV model has excellent sound quality. I have one on the shelf in the workshop which once saw service on my workbench when I was doing my apprenticeship and it was one of the first radios I collected. Seeing this thread has given me the thought of digging it out and doing a full restoration on both the chassis and cabinet.

A lot of that crap is stearate from fat rather than petroleum based.

If the gang has trimmers try and keep water out of them as you will need to get it out if they get wet (metho).

You can remove the tuning gang if water is going to be a problem. I normally find Aluminium Wheel cleaner which foams like shaving cream, can move dirt from within the plates. Otherwise use Soda Ash solution & do not leave it on bakelite for an extended period. Its residue can be removed with water. Do not get Soda Ash solution on a Bakelite cabinet.

Soda Ash (Soduim Carbonate aka Pool Soda Ash) is also good for removing "mouse do from" wafer switches (with brush) same deal with the bakelite.

There were often tappings on the transformer to feed the globes & reduce the brightness & heat. I have seen other sets with resistors of that order.

It is not unusual to see unused valve pins used as tag strips albeit 5Y3 is the more common to have this done.

The hassle is using Pin 1. If its used and a metal valve is used: Things can get quite interesting, as Pin1 on an Octal metal is the outer shield.

Marc

Thanks for the response, tips & links everone
Looks like it will have to come out, I don't want to risk the paint on the chassis as its still in very good condition.
Tried some contact cleaner today as a last resort but its just to weak a solvent
I was hoping not to really disturb it as it has an interesting gear drive which has fine & course tuning with a shaft in a shaft setup. Very clever.

Recently finished working on a HMV 886 for a friend which is a later model from 1947, - almost identical chassis & components but oddly that feature was not present....

Strongly agree with your statement Brad about the sound quality...the 886 I worked on sounded magic & I was reluctant to part company with it!! I hope this 881 will sound as good when finished.... 886 had an 8" inch speaker & my 881 a 6.

Anyway, cheers all

Yes, I have one of each though my larger version (actually the third radio I ever collected back in 1989) had a rather dodgey speaker repair (done by a fairly inexperienced collector at the time [me]) and it doesn't sound as good as the smaller model. One other thing is the cabinet - HMV put stickers on top of these receivers which were similar to the old rego labels for cars and on these radios it was the 'Sydney, NSW' version instead of 'Middlesex, England' one found on HMV grammophones.

Some collectors have reproduced these in the past but I don't know if they are still available and something like this would be fairly important to a set like these I reckon. Apart from the speaker repair and cabinet refurbishment to the larger receiver, these two sets of mine remain unrestored and thus I am unable to use them at the moment.

Quite right with the fine tuning vernier on the 881 too. When I bought my 881 about six months after the 886 I was worried that the 886 had been butchered by a backyard boy.

I think there were two versions of these receivers too. One, perhaps a later update, had extra flutes in the woodwork around the edges of the cabinet.

STC used resistors like this in their late '30s radios. 400 to 5000 ohm for cathode bias. They looked like they were wound on a brown fiber former.
I never investigated this though since they were all in spec. Might have been a low grade mica.

Fortunately decals are avail through a HRSA member which are very close to the original, available with red or gold text.

http://s860.photobucket.com/albums/ab167/pjfitzy/HMV886%20Resto.

Don't seem to have a pic of the radio with new decal. Will get one when the final piece is sourced & put back on.......the dial control overlay piece which is made from some sort of cellulose film. It has warped & yellowed with age so much it detracts from the radio. Hopefully one can be reproduced for a reasonable price.

Regards
Paul

When I restored my 886 back in 1989 I ditched my control overlay. Unfortunately cellulose doesn't survive the test of time and mine was actually in two pieces anyway. The radio actually looks fine without it.

After looking at your receiver something else has come to mind. Mine required me to make new speaker grille bars and due to lack of woodworking equipment at the time I hand-carved the rebates along the edges of the bars and ended up neglecting to colour them as per the originals. I did a fairly good job on the rest of the set so there is an opportunity for me to do a supplimentary restoration of the cabinet to finish the job correctly.

As for the HMV transfer, this is the time I wish I was still a HRSA member. I wonder if they'd let me have my old member number back...

I also took the liberty of fixing up your avatar. I hope you don't mind. When you use the Gravatar service this site will automatically detect this so members don't need to insert a URL to make it work.

Brad:

"Some collectors have reproduced these in the past but I don't know if they are still available"

Try Michael Raanan (raanan (at) optusnet (dot) com (dot) au)

I believe he makes reproduction transfers, so you might be lucky.

If you take the gang out, then you can also resort to laundry powder in warm water. I am not at all surprised that solvent is useless.

The reason for Soda Ash (do not use Caustic Soda; It eats Aluminium) is that it will convert the kitchen fat (stearate) into a crude soap. A little bit of dishwashing liquid in with it also helps.

If you want to try this as a damp wipe, try it in an inconspicuous place, to make sure that it does not effect the paint.

Marc

Thanks all...will try the laundry detergent idea first, if that doesn't work then into the dishwasher..
Michael is still making the decals $18 ea +P&H
Red text or Gold,
Red 881 & Gold on 886...maybe depending on unit finish.

Cheers Paul

Dishwasher worked very well, all grease & grime removed from everywhere even the bearings..
Would not recommend diswasher if the plating on the steel bits of the tuner frame have poor condition plating...the dishwasher turns it into instant surface rust.
Easily cleaned & treated but something to be aware of.

Result was pretty good, so thanks all for the ideas.
Removal of the tuner also helped solve another issue that this radio suffered from since I obtained it .....
When tuning from the 1600kHz end at about the 855kHz mark it seemed like all stations beyond this point compressed into a very small area leaving the rest of the tuning dial dead.
Turns out some of the vanes were touching each other at this point of the rotation. Some fiddely adjustment later & now the whole dial is alive...probably any easy conclusion to that fault for the experienced tech heads, but for a newbie like me a great relief at such an easy fix for a problem I had considered possibly a component or alignment issue...

As they say - alls well that ends well

Cheers all
Paul