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 Astor HM restoration update
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 Return to top of page · Post #: 1 · Written at 8:34:59 PM on 11 February 2020.
mawdryn's Gravatar
 Location: Gosford, NSW
 Member since 4 December 2005
 Member #: 7
 Postcount: 45

Hi Everyone,

just thought I'd post an update of my restoration efforts for my Astor HM.

Phase 1 - Rejuvenate radio component is pretty much complete. (except some decorative work.)

Below are some photos of the work done so far.

https://ibb.co/Jvky03g
https://ibb.co/99G8GH0
https://ibb.co/M1x7Wjj (Facia still needs to be repainted)

I've left the original can caps mounted for aesthetic reasons.

I probably need to get someone to give it an alignment, as I don't have a CRO or a signal generator.
I don't suppose anyone knows anyone on the NSW Central Coast who does that sort of thing?


 
 Return to top of page · Post #: 2 · Written at 9:45:19 PM on 11 February 2020.
Marcc's avatar
 Location: Wangaratta, VIC
 Member since 21 February 2009
 Member #: 438
 Postcount: 3865

I use an oscilloscope as I have them and they tell me lots about the signal. However, most of the Astor sets will have a capacitor, perhaps RF decoupled close to the OP tube and connected to a socket and the plate of the OP tube. That is for originally, an analogue meter on something like the 5V AC range.

That is for peaking the IF's, so you do not really need a CRO if you have none: Most early service people didn't as they were not cheap & you really needed to be professionally servicing, or later on servicing TV to really justify the spend.

Marc


 
 Return to top of page · Post #: 3 · Written at 7:34:04 AM on 12 February 2020.
STC830's Gravatar
 Location: NSW
 Member since 10 June 2010
 Member #: 681
 Postcount: 846

Re photos, nicely done.

I have an old magazine article which comprehesively covers alignment without a CRO. I can email if you unhide your email adress.


 
 Return to top of page · Post #: 4 · Written at 10:26:59 AM on 12 February 2020.
Marcc's avatar
 Location: Wangaratta, VIC
 Member since 21 February 2009
 Member #: 438
 Postcount: 3865

As a sideline but relevant. The "Peak" 200H meter has a dedicated socket "Output" (Have one). This has a 0.1mfd series cap and is for calibrating using the 400 to 1KHz single tone from a signal generator.

This of course prompts a warning to check the caps if you have an old meter. The 200H one was paper, and cactus, an AVO 7x had one let go and there is a litany of test equipment that has gone across my benches over the years.

There is absolutely no place for NP caps that leak to any extent, in test equipment.

Marc


 
 Return to top of page · Post #: 5 · Written at 7:01:47 PM on 13 February 2020.
mawdryn's Gravatar
 Location: Gosford, NSW
 Member since 4 December 2005
 Member #: 7
 Postcount: 45

STC: Thanks. I'd appreciate it. Email unhidden.

Marcc. Sorry - Stupid question, but what's an OP tube? (output?) - I've never touched a vacuum tube before beginning to restore this unit and I've not encountered this term while researching other than your posts here and on antiqueradio forums.


 
 Return to top of page · Post #: 6 · Written at 8:02:14 PM on 13 February 2020.
STC830's Gravatar
 Location: NSW
 Member since 10 June 2010
 Member #: 681
 Postcount: 846

Procedures sent, good luck.


 
 Return to top of page · Post #: 7 · Written at 10:21:37 PM on 13 February 2020.
Marcc's avatar
 Location: Wangaratta, VIC
 Member since 21 February 2009
 Member #: 438
 Postcount: 3865

I am a moderator on an American Forum & lots of different terms get tossed around. OP Tube (output tube) US: Electron Tube (Philips); Valve here. In a radio, or amplifier is the one, or ones that end up driving the speakers.

The term "output" is as noted, often on Multimeters of the era like 200H, also refers to the Audio output Valve, where the meter is measuring the AC component of the tone as a voltage off of its plate.

Radio is not simple.

Marc


 
 Return to top of page · Post #: 8 · Written at 11:04:44 PM on 13 February 2020.
mawdryn's Gravatar
 Location: Gosford, NSW
 Member since 4 December 2005
 Member #: 7
 Postcount: 45

STC, Thanks got the guides. Cheers

Marcc, Thanks. I guessed that's what you meant, but doesn't hurt to clarify Smile I just checked the schematic and it does show an output test socket between the speaker transformer and pin 3 of the 6V6.

I'll at least have to get/build a signal generator... Wish me luck. At least I have alignment instructions with the schematic.. Looks like I have some reading to do.


 
 Return to top of page · Post #: 9 · Written at 12:00:57 AM on 14 February 2020.
Marcc's avatar
 Location: Wangaratta, VIC
 Member since 21 February 2009
 Member #: 438
 Postcount: 3865

Silicon Chip did describe one as a kit a while back; There is a Leader LSG-11 here basic sort of thing, I have a clone of it. Don't really care about the accuracy of its dial: I set it with a frequency counter. The leader needs a new transformer. Secondary 100V & 6V for two valves. Have not been looking to hard for one. If some one needs it … then it can be fixed.

There is a Sanwa one that turned up here. Don't know a lot about it, but as its shelf queening where it is. Tag says it was overhauled 2012 so it would need a recheck to make sure the filters are ok.

Alignment is a black art with many pitfalls for the unwary and those who do not understand. Bad alignment is the principle reason for "deaf" sets. (I.e. inability to receive stations)

Marc


 
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