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 Return to top of page · Post #: 31 · Written at 10:49:06 AM on 14 July 2020.
Ian Robertson's Gravatar
 Location: Belrose, NSW
 Member since 31 December 2015
 Member #: 1844
 Postcount: 2370

Re Notre Dame in Paris, yes Marc you are on the money there. I believe that is the case.

I think the issue of house fires caused by VIR would be more common today except for the fact(?) that most houses that were wired with this stuff have already burnt down!


 
 Return to top of page · Post #: 32 · Written at 11:53:45 AM on 14 July 2020.
Brad's avatar
 Administrator
 Location: Naremburn, NSW
 Member since 15 November 2005
 Member #: 1
 Postcount: 7301

There's still lots of houses and other buildings with VIR cable. It is perfectly safe if it is still inside the split seam conduit that it had to be installed in. Where it fails is at light fittings where heavy light globes have been installed and dried out the rubber insulation with excessive heat.

The other issue with VIR isn't so much the state of the insulation but the ease at which it can be overloaded. Its cores are not as thick as the metric cable we use these days. Light cable was a single solid strand - illegal in new installations. Power cable was 3 strand instead of 7 strand, so there was less 'meat' to screw shut on connections.

Interestingly enough, there's still lots of houses with rewirable fuses and no RCD protection too.


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A valve a day keeps the transistor away...

 
 Return to top of page · Post #: 33 · Written at 7:19:16 PM on 14 July 2020.
Jimb's Gravatar
 Location: Kanahooka, NSW
 Member since 18 November 2016
 Member #: 2012
 Postcount: 712

Hello again all.
Marcc I had already replaced R 24 3k resistor however in the back of my mind I thought it was lite on. I then referred to the parts list and yes it is supposed to be 1 watt. Having read your post I removed it and paralleled up a 5.6k with 6.8k to make up a 2 watt resistor .
Finished it off today powered it up and the front end was dead. Checking I found I had not wired up the filiament on the 6BE6. Radio now works. Not sure what to expect, I replaced the faulty audio output transformer with a Jaycar unit. If I crank up the volume it sounds nasely for want of a better description. All the voltages look good, the bias voltage on the 6BV7 is minus 4 volts as per the circuit. I have tried altering the secondary tappings and can't notice any difference the secondary side is 8 ohm and the speaker is 3 or 4 ohm has this something to do with it? I have tried swapping the secondary winding connections again just the same. At normal listening level it is fine if I crank it up to full volume it sounds nasely . What should I expect from that little speaker? My wife Robin thinks it sounds ok at normal listening level. I am rather pleased it works at all I did not find it an easy repair.
I ended up using the white cotton covered 3 core I bought off Carl.
Regards Jimb.


 
 Return to top of page · Post #: 34 · Written at 9:28:30 PM on 14 July 2020.
Marcc's avatar
 Location: Wangaratta, VIC
 Member since 21 February 2009
 Member #: 438
 Postcount: 5254

Actually, a mate has a house that's weather board over a 100 years old is full of it & should be razed inside 20 minutes if it gets going. The dumb meter installer took one look in the meter box, got for his life & has not been seen on site since.

Owner was told by me, when roof repairs were being done, to not step on the wires, or conduit, nor touch it and when he upgrades anything electrical that there is a power pole over there and that's where you start the rewiring.

In preparation for constantly rewiring these things, I do keep colours in stock. That way you can keep things separate. E.g. Heaters green, primary & secondary HT: Shades in red orange, Screens Blue etc.

There is the probability that the speaker is "poling", especially if it has been damaged. The easy way to prove that is to disconnect it & sub it with one that's known good. That does not mean remove it.

If you have the gear, its always a recommendation, from manufacturers after interfering with RF components, to recalibrate the IF.

White mains cord should contrast with Blue.

Marc


 
 Return to top of page · Post #: 35 · Written at 9:55:31 PM on 14 July 2020.
Jimb's Gravatar
 Location: Kanahooka, NSW
 Member since 18 November 2016
 Member #: 2012
 Postcount: 712

Hi Marcc.
Yes I could try another speaker. The radio is reasonably sensitive as rule I prefer not to stuff around with alignment unless necessary slugs are too easily broken.
Regards Jimb.


 
 Return to top of page · Post #: 36 · Written at 11:19:47 PM on 14 July 2020.
Marcc's avatar
 Location: Wangaratta, VIC
 Member since 21 February 2009
 Member #: 438
 Postcount: 5254

I have never seen one break in one of those screw type IF slugs. Transistor radio types: Yes some of them were ill conceived.

I have only ever had to make a new slug for a Valve radio padder, as its was missing and that was entertaining. I made it from a chunk of ferrite antenna. Never try and drill, or cut it with metal, or tungsten carbide. To turn it, it was a tool post grinder with the rod wrapped in paper to stop it shattering. Since then a whole box full of brand new ones fell into my lap: Great after the event.

Marc


 
 Return to top of page · Post #: 37 · Written at 8:41:53 PM on 15 July 2020.
Jimb's Gravatar
 Location: Kanahooka, NSW
 Member since 18 November 2016
 Member #: 2012
 Postcount: 712

Well the nasal audio appears to have been caused by the Jaycar audio output transformer. I replaced it temporarily with a larger genuine radio one and the audio is okay. I cannot leave this in because it physically does not fit. I will go back and see Tony and rake through his late Dad's stuff I am sure we will be able to find something that will do.
Marcc I had a gentle trial at the if transformer ferrite slugs they do not want to be moved from their resting place of 68 years. I have not actually altered the Rf path. I have only replaced rotten wire, coupling capacitors and electrolytic capacitors. I have also replaced V3, 6U7 and the 6BV7 it was making nasty crackling noises. Unfortunately I did not have a new one because I gave the two I had to a bloke I did not even know because I thought I was all done doing repairs. However the second hand one is OK.
Regards Jimb


 
 Return to top of page · Post #: 38 · Written at 10:02:53 PM on 15 July 2020.
Marcc's avatar
 Location: Wangaratta, VIC
 Member since 21 February 2009
 Member #: 438
 Postcount: 5254

It depends on what bog they used to hold the screw, but it is normally confined to the screw. Often it was only hard wax.

The manufacturers recommendation re RF section covers any part be it valve, capacitor, or resistance.


Many line transformers are not designed to handle DC. If you are really stuck I may have a 7K for it. New is an option.

https://au.mouser.com/datasheet/2/177/1750-736917.pdf

Marc


 
 Return to top of page · Post #: 39 · Written at 10:40:59 PM on 15 July 2020.
Jimb's Gravatar
 Location: Kanahooka, NSW
 Member since 18 November 2016
 Member #: 2012
 Postcount: 712

I think I will be OK thanks Marc.
He has stuff every where when he finally sells his house in Sydney and moves here he will be wanting to get rid of it
I am repairing a few radios he wants to keep. The rest will be sold off cheap along with loads of test gear some I have no idea of it's use. I have no interest in any of it. He might sell this Astor Mickey because he has an Empire State he wants repaired. It will be expensive because all the speaker cone has gone for a start, at this stage I suggested to him he gets a professional restoration done, not sure if I want to get involved with it.
I will let you all know when he has moved and if it is OK with him I will give out his phone number I don't want any personal involvement with any of it.
Regards Jimb.


 
 Return to top of page · Post #: 40 · Written at 12:32:23 AM on 16 July 2020.
Marcc's avatar
 Location: Wangaratta, VIC
 Member since 21 February 2009
 Member #: 438
 Postcount: 5254

Yeh! Some sets can be utter swine's to repair, but I am still getting a few trickling in for commercial repairs. About 2months ago I started on a HMV 5101 (now mine) however, around here fixing has a very broad spectrum. Currently I seem to be on a fencing cycle. I have pretty much sorted out the neighbours main electric fence & it seems to want to maintain 5KV; meanwhile I am sorting out one of mine. At one point there was a chainsaw sitting in front of the HMV. Amazing what you find on that bench. Albeit the kitchen table has a chair on it, waiting for the glue to dry. No woman to complain about that or practicality of the outside toilet seat always being up to discourage the fauna.

There was an incident with a headlight door on the Ute & that got sorted, I put the tractor back into service in January, but its now in the line as the time has come to re-tighten the cylinder head and reset the tappets & governor. Still have some storm damage cleaning up to do.

Currently I am having an argument with Nr 1 computer (XP); Still have to see why the NVIDA power supply is playing up on the Toshiba that was replaced by this one. Meanwhile I have found a support person for the printer, who is totally mechanically challenged. If you get a bad line repeated around every 90mm that is a mechanical fault with the roller, or drive not a cartridge.

Really a dull moment here is elusive.

Marc


 
 Return to top of page · Post #: 41 · Written at 9:19:10 AM on 16 July 2020.
Jimb's Gravatar
 Location: Kanahooka, NSW
 Member since 18 November 2016
 Member #: 2012
 Postcount: 712

Sounds like you are not going to suffer from Boardom anytime soon Marc.


 
 Return to top of page · Post #: 42 · Written at 10:07:12 AM on 16 July 2020.
Tinkera123's Gravatar
 Location: Melbourne, VIC
 Member since 5 October 2009
 Member #: 555
 Postcount: 465

Re; IF slugs ....
I have had a few 'fights' with IF slugs .... but only ever had broken slugs with the hexagon shaped key hole, not with the slotted slugs. Also, all the broken "hexagon' keyed slugs were in paper / wax coil formers ... so not sure if the problem was caused by the style of slug or former. I breathe a sigh of relief when I find that a radio has the plastic type coil formers and slotted slugs. As per Marcc, I also became the benefactor of a supply of correct slugs after many fruitless searches and shipping some from USA at extortion rates.

Week 1 of our Lockdown done .... shortest day of the year gone ... Spring is only a few weeks away .... a couple of great projects await my attention ..... Smile Smile

Stay safe.


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Cheers, Ian

 
 Return to top of page · Post #: 43 · Written at 12:36:13 PM on 16 July 2020.
Ian Robertson's Gravatar
 Location: Belrose, NSW
 Member since 31 December 2015
 Member #: 1844
 Postcount: 2370

Jim, with the PA transformer, with the higher currents drawn by mains output valves you need to "gap" the transformer core.

You can re-stack the E and I laminations so they are the same as the old tranny.
Pull it apart - that's the quickest way I can explain it.
You can use a piece of tape as the air gap.


 
 Return to top of page · Post #: 44 · Written at 12:47:32 PM on 16 July 2020.
GTC's avatar
 GTC
 Location: Sydney, NSW
 Member since 28 January 2011
 Member #: 823
 Postcount: 6687

You can re-stack the E and I laminations so they are the same as the old tranny.

Making sure that you do so exactly in the original orientation, taking notice of which side of the lamination is insulated.


 
 Return to top of page · Post #: 45 · Written at 7:11:16 PM on 16 July 2020.
Jimb's Gravatar
 Location: Kanahooka, NSW
 Member since 18 November 2016
 Member #: 2012
 Postcount: 712

Thanks for the transformer advice . The way I am I would be surrounded by transformer laminations . Tony H is bringing me some scrap chassis's next Monday I am sure there will be something of value amongst them. If not I will seek further transformer reconstruction guide lines from you guys. I try and work within my physical limitations .
He is sending me some pictures of a bit of test gear apparently there is one in the power house museum he wants it gone it is in his house in Sydney . I will keep you posted on this it is not a case of wanting megger dollars for it he needs to get rid of it.
Regards Jim.


 
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