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 Astor NJ problem... Any Idea's welcome.
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 Return to top of page · Post #: 1 · Written at 10:18:46 PM on 8 October 2016.
JamieLee's Gravatar
 Location: Clare, SA
 Member since 27 March 2016
 Member #: 1894
 Postcount: 510

Hello guys, I'm really stumped on this old Astor, I have replaced all of the caps and out of spec resistors and can't get any reception, I get "cartoon radio noises" at a certain part of the dial, from another radio I'm listening to, indicating that the tuning section is working. If I touch the wiper of the volume, I get loud noise indicating the amplifier (6V6G/GT) is amplifying well, but something is amiss with the voltage readings I am getting. I'm getting a strong 267v at the 6A8G pin 3, connected to IF 1, (43 on the schematic), I have 270v at the 6V6G/GT, whereas I'm supposed to only have 250v and 245v respectively on pin 3 of these valves. But that's not what's really got me scratching my head! On pin 3 of the 6B8G connecting to IF2, I'm supposed to (according to the schematic) have 130v, but there's a whopping 270v there! Coming straight through R32 which is brand new and testing at 60K ohms, which is supposedly spot on??? Something's not right here and either I'm missing something very simple or God only knows? Very strange indeed... Does anybody recognise or have some insight what could cause such an anomaly? Or is the 130v on the schematic a misprint? Seems that the voltage can only be getting through that 60k resistor, which is in spec. so I'm totally stumped, maybe could the IF be short circuit? But nope 16 and a half ohms there... Which surely wouldn't drop 140v if 60k only drops 1 volt? Somehow there's an extra 140v coming from lord knows??? Hmmnnn.....

http://www.kevinchant.com/uploads/7/1/0/8/7108231/nj.pdf


 
 Return to top of page · Post #: 2 · Written at 12:09:28 AM on 9 October 2016.
JamieLee's Gravatar
 Location: Clare, SA
 Member since 27 March 2016
 Member #: 1894
 Postcount: 510

Oh dear, what a clown am I???
I found the problem and now this radio looks and sounds absolutely awesome!
In the schematic pin 6 of the 6A8G is 70v, voltage was present, but where pin 4 of the 6B6G isw supposed to be also reading 70v, I had 0v, then discovered in my zeal to replace old rubber insulated wires, which were cracked and perished, I got a bit ahed of myself and forgot to replace the wire connecting pin 6 of the 6A8G and the 6B8G, after cutting the old one out.
Silly of me, and I was going to delete this post, but for anybody learning about radio's, it may be useful, as all of the voltages which were out of whack in my last post, all pulled into line once I replaced this wire s it was supposed to be! Phew...


 
 Return to top of page · Post #: 3 · Written at 1:20:34 AM on 9 October 2016.
GTC's avatar
 GTC
 Location: Sydney, NSW
 Member since 28 January 2011
 Member #: 823
 Postcount: 6687

I got a bit ahead of myself and forgot to replace the wire connecting pin 6 of the 6A8G and the 6B8G, after cutting the old one out.

Easily done. I replace one wire at a time for that reason.


 
 Return to top of page · Post #: 4 · Written at 10:02:32 AM on 9 October 2016.
Marcc's avatar
 Location: Wangaratta, VIC
 Member since 21 February 2009
 Member #: 438
 Postcount: 5254

There are traps when you have not a developed methodology. As I have said many times, turning it on unchecked to see it it works is not best practice.

A case in point:

I sent out a Kriesler 11-20 yesterday. This had been repaired 1951,1967 and the red green caps on the 6V6 & new filter caps, said very recently. That's where the joy ended.

It had a two wire, probably original mains cord, now a black cloth covered one with decent anchorage; Only the caps mentioned had been replaced, all of the rest of the Wax paper ones were still in situe: The dial lights were sitting on the chassis & a hack repair had been done. The rubber was hard and inflexible & one was a write off. For the benefit of others a globe holder like Jaycar SL-2658 mounted in a grommet sorted them.

It left with three original resistors, (not on the 6V6) there were issues with the dial mechanical's fixed as part of calibration; Unusual for a Kriesler the speaker transformer was good, normally about two in eight are, however the speaker was poling (wildlife). Jaycar have discontinued AS-3010 but I had one.

Calibration was not overly eventful after I soldered a Brass washer onto the Ist IF can's adjusting screw. Perhaps it would not have broken if someone had replaced that which was throwing it off & did it properly in the first place (or left it alone). Only other wire needing replacing or was, was a valve fly lead, dial lights & that involved in re-locating the speaker transformer and the antenna wire as it was shorted in the pan.

And you wonder why the owner bought it and brought it straight to me to be checked before use.


 
 Return to top of page · Post #: 5 · Written at 5:11:50 PM on 9 October 2016.
JamieLee's Gravatar
 Location: Clare, SA
 Member since 27 March 2016
 Member #: 1894
 Postcount: 510

Yes well ,my methodology is getting better, I replaced every cap here and all of the wires with crumbly insulation and all out of spec resistors before I powered it up. One wire at a time I will from now on!!! It's definitely my best result, it sounds really good, loud and clear and tunes well. The good advice I have been given on this forum has been an invaluable resource. I wouldn't think of plugging one in to see if it works anymore, without replacing all paper and electro caps and crumbly looking wiring!


 
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