General advise please (HMV1115).

[HMV 1120]

Pretty please!!

The HMV 1115 is down off it's shelf, and it's innards currently spread across a boarding house table. Thanks to the generosity of 'Setsappeal' I have the parts to strip and relace all the problem caps, and should have that done this evening.

The cabinet however, looks a bit of a mess. It has solid wooden sides, plastic front and plywood top. The dial is glass with back printing. As this is my first proper radio restoration, are their any 'do's and don'ts' I should be aware of before I try and clean it?

I know this a basic question, but I want to do it properly so that it lasts, and this forum is the ideal place to draw upon such experience.

Thankyou in advance, Rob.

[paulsherwin]

Be very careful if you clean the printed side of the tunung scale. The ink on these things is usually water soluble and will disappear if you get it wet. If in doubt, don't clean that side at all.

Good luck, Paul

[Nickthedentist]

In addition to Paul's wise words:

Don't slip with the screwdriver when removing the dial glass. It's SO easy to do, and will wreck the screenprinting.

Once you've removed it, just brush off any dust or grit from the printed surface with a gentle wipe using a soft duster. Then place the scale, printed side down, on a few sheets of clean newspaper on a flat table.

Then you can clean the plain (external) surface quite vigorously without fear of damaging the printing. But do be sparing with whatever liquids you use, so that they don't seep underneath and attack the printing.

Finally, put it somewhere very safe, where it's not going to be broken.

Good luck,
Nick.

[Hermit6345]

Hi Rob,

Good luck with that restoration. I wonder, did you ever fix the previous fault or is this an ongoing part of that? If the radio is working I was going to suggest that you replace one capacitor at a time and check that the radio still works after each replacement. It can be a pain if you change the lot in one go, the radio doesn't work and you are not sure whether it's something you have done or whether the fault is elsewhere. This can be especially relevant if the components are on tagboard. Easy to get a component lead on the wrong tag. Agree re the comments about the dial glass, take great care of that. Cabinet restoration is another thing though!

Ian.

[Robert Darwent]

Hi Rob

As regards cleaning the printed side of the dial glass. I read somewhere (I forget actually where, but it may have been one of Tony Thompson's books) that a good method is to breathe on the dial glass, as you would in order to fog up a window pane, and then very lightly rub that area with a clean cloth. All the while checking you are not doing any damage to the print.

I've used this method successfully on several occasions. If you take your time and are careful it really does work. Its surprising what a tiny amount of moisture from your breath will remove in terms of accumulated dirt and yet is insufficient to start lifting the print. However to be on the safe side always try it on a inconspicuous edge of the dial first in case the legend on your glass is really flakey.

[HMV 1120]

Thankyou all. The glass proved a little fiddly to remove, but is now out and relativly clean - I didn't force the grime that stuck to the print edges, but it looks much better. The plastic was washed with hot soapy water, and that seems to have done the trick.

Hermit - Yes, I've replaced the caps one at a time untill I ran out of new parts. There are still two electrolytics in there, and a few mica waxes. The problem is vastly improved but still sounding like gravel, as well as weak.

Interestingly, C12 (o.o47uf) was missing - it had never been soldered in! The trader sheet lists it as 'Valve 2 Cathode Bypass', and states it is absent in the first few production runs. I guess I have an early set then!!

I have a replacement cap for it, should I insert it? Or not worry seeing as it ran without it during it's 'working' life?

[Hermit6345]

Hi Rob,

I think I would install the cathode bypass cap anyway as I guess that the manufacturer thought it was necessary in later production models. If the radio were mine, once I had replaced everything, I might be inclined to run a sig. gen. over it just to check sensitivity etc.

Regards,

Ian.

[HMV 1120]

Then it will get added to the list. The set is back in one piece now, giving reasonable service when the aerial is fed to the top cap of V2. It is not entirely fixed, but atleast I know these replaced parts are good for another sixty years.