Now that I have finished my Tasma 1001 restoration I'll make a start on my 1005.
This set must have been owned by a smoker in the past!

Lovely radio and a significant model in the Tasma range.

Keep in mind many people of that era had open fires, wood fire or coal heaters of various kinds which may have resulted in the grubby deposits.

Have seen a number of old sets in such as state, perhaps methylated spirits would help.

I have a Tasma that has just come in an is about number 3 in the radio repair line. Not same model as that as the tuner is rear centre, However, it is covered in what you will likely find, and is quite common, fat.

A damp cloth with soapy water will get that off of the valves & chassis, but stay away from the letters on the dial. Most of those are flimsy at the best of times.

The numbers often come of some tubes so know what it is important to do them one at a time & scratch the number on the base. Lever the Philips ones out or you may damage the bond between metalisation and base.

Marc

Hi there its George I sold you this Tasma I don't think there is anything to do to it as it had most components replaced I should know.
George

Restoration could mean different things to different people George
The last thread, he stripped a radio down to it's chassis,
which I think, is the only decent way to paint a chassis.

What's the big resistor doing? Just impedance matching?

Big resistor is likely acting as the choke?

Ah makes sense .. if the field coil was good but the choke was stuffed.
Or, sine the resistor is an Australian product, maybe it is the choke.

Not a good spot for wandering fingers (then if you stick them in such places ... tough) but ideal for cooling.

Marc

If that's a comma I'm going to say field coil speaker replaced
with permanent magnet speaker,
and 2,000 Ohms was the field coil impedance.
Pretty much what I'm about to do.

Still high voltage, but I was going to put mine on the speaker too.

The circuit says that replacement should be 2K for a Permag speaker. Make sure if there is a set of taps on the transformer it is on the appropriate one. I have mounted them on a tag strip on the inner side of the pan.

B+ is quoted as 225V (which will be +/- 20%). If the set is running correctly there should be -1.6V across the 400R backbias resistor. Chassis will be positive when measuring that one.

The most common cause of high voltage is poor conduction.
Check the 400R resistor, if there has been a heater cathode short it may be damaged.

Marc

I have a Tasma 710 radio, which is a earlier dual wave 5 valve version (same cabinet) of the 1005, dating from about 1940.

This too has had the electro-dynamic speaker replaced by a permag type. The field-coil was replaced with a Rola type 14/60 choke (D.C resistance, 550 ohms) in series with 2 x 5 watt resistors also in series comprising of 720 & 500 ohms. Total resistance 1770 ohms.

I haven't used this radio for about 10 years and after reading this thread thought I'd have a look at it. I couldn't fire the radio up anyway as I "borrowed" the output & rectifier valves for another project ages ago. So I measured the choke and got a reading of about 500K. So something is not quite right there.

Since this radio was one of my earlier attempts at a restoration (I've learn't a lot in the past 15 years!!), I'll tidy it up a bit before firing it up again. Since the choke appears to be stuffed, I too will go for the 2000 ohm resistor replacement. Also whoever replaced the speaker and installed the choke & resistors all those years ago wasn't very tidy about it.

Question for Marc:

What wattage should the 2000 ohm resistor be?

I also noticed the mods in the back bias circuit for the 1001 when using a permag speaking. Do I need to look at that as well? Circuit wise my 710, though being D/W, appears upon first glance close to the 1005.

Hi George,
Dont get me wrong I am very happy with radio.Its cleaning up nicely.
Here is the chassis now.

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I completely strip and refurbish all wiring and all components so that when I am long gone the radio will still be going. Probably no AM stations on air!
The wiring in these old radios is very brittle and the insulation has already deteriorated. So I replace that as well with modern wire that looks the same as the old wire.

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Here is the new harness.

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The 2K resistor is 20W.

In the earlier radios they used the field coil as an electro magnet for the speaker. It also served the purpose of an LC filter to filter the 100Hz hum from the HT by having an electo on either side of the coil. They went to resistor as an RC filter to do the same job. The resistor and Permanent magnet speaker was cheaper than using a field coil in the speaker.
I’ll post photos of the finished project soon.
Cheers,
Gary
l

Dont tell the Wife, but the best way I have found to clean IF cans and tuning capacitors is stick them in the Dishwasher. Coils taken out of cans and the tuning capacitor well greased after drying. Use conductive electoronic grease on the capacitor
What do you think?

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This is as far as I have progressed on the 1005 resto. Too many Xmas events happening.

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All the best to you and yours for Christmas,
Gary

What dishwashing product is it Gary?
I'd like to get a tuner gang looking like that.

Because our discreet components are smaller,
it ends up looking odd because there is too much wire.
If you haven't figured it out already,
That EVATCO vintage wire, if you cut a length the same as
a capacitor lead, you can then bunch up the sheath at one end,
and then slide it straight onto the component lead.
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I really like what you're doing.
Something a lot of people could do, but wouldn't go that far
because it's a lot of work, and some risk of error.

Sometimes I like the colour/texture of an aged chassis, and wouldn't choose to.
I noticed that when I had a few junk chassis.
Some I would want to paint, and some I would want to leave alone.

I have used the dishwasher to clean variable caps - works quite well. Any automatic dishwasher product should be OK as they work in this application because both the aluminium plates and the zinc plated steel frame react with the alkaline solution. Just seems to brighten them up without pitting or stripping off the plating.

A good soak in washing soda (sodium carbonate ) works well too, though a bit of elbow grease with a tooth bush may be required. Dissolve the soda in boiling water to speed up the process.

This idea was mentioned in an English forum post, which also recommended it for complete chassis being kept for display only - going a bit far I think.

Unfortunately doesn't help if the cap frame is rusty. Short of dismantling and re-plating, the rust could be ground back to bright metal and lacquered. For the case I have I intend to make up a grey and silver paint mix and try and match the plating, just in the rusted areas.