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Old 6th Feb 2019, 10:09 pm   #1
CesarLG
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Default Hammarlund HQ-129-X caps

Hello!

I am recapping my Hammarlund and I have found that my electrolytics differ feom those listed in the manual. What do you think guys?

My radio has:-
10uF 500V
20uf 450V
20uF 450V

In the manual, those filter caps in the can are 10uF 450V

By the way, do you know if there is a trimmer to adjust the smeter?

Thank you.
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Old 7th Feb 2019, 12:37 am   #2
Dave757
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Default Re: Hammarlund HQ-129-X caps

Hi Cesar

The S meter adjustment is on the top of the chassis between the
6V6 and 6SN7 tubes, as described on page 8 of the manual. There is
also a picture on page 11 showing the location.

I can't help with the caps, but it might be worth looking at the
refurbishment of the HQ120 and HQ140X receivers in the 'Mr Carlson's
Lab' series on YouTube.

Kind regards
Dave G0ELJ
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Old 7th Feb 2019, 6:10 am   #3
Argus25
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Default Re: Hammarlund HQ-129-X caps

It would depend which section of the capacitor is used directly on the output of the rectifier, if it is the 10uF section, then it probably makes no difference that the other values are larger downstream in the HT filter system, you might even get less hum. The main thing when replacing these is to:

1) don't exceed the original uF value that is connected directly to the rectifier output.

2) always use the same or a higher voltage rated electro to replace it.

3) always use new manufacture electros, don't use very old stock or re-formed electros unless you want reduced reliability.

Probably something like this would be fine too, AES have a good range of these, this is just one:

https://www.tubesandmore.com/product...f-electrolytic
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Old 12th Feb 2019, 8:23 am   #4
CesarLG
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Default Re: Hammarlund HQ-129-X caps

I have changed all caps with modern ones. I used 10uF on all caps inside the can. Also 20uf on the other electrolytic hangin out.
On the rest I used 630v polyester caps.
Now the output of the bfo is better, and the overal performance is fantastic. The only thing still persists is an overload on the smeter. It is always full scale, no matter the setting or the signal of the station. I have adjusted the potentiometer and also the nut on the front pane.
Could I just place a trimmer in the input wire to the smeter? I am sure there must be a resistor with a bad value somewhere. I have been chasing one by one but some of them are in funny locations...
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Old 12th Feb 2019, 9:22 am   #5
HamishBoxer
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Default Re: Hammarlund HQ-129-X caps

Could even be R41 gone high.
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Old 13th Feb 2019, 10:38 am   #6
CesarLG
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Default Re: Hammarlund HQ-129-X caps

I checked that and it is fine. I have been looking at all resistors with no luck. Could it be a a problem with a tube?
What I have made for now is putting a 1M resistor in the smeter wire to save the needle smacking against the bar end. I have measured 230v on this wire
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Old 13th Feb 2019, 10:16 pm   #7
CesarLG
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Default Re: Hammarlund HQ-129-X caps

I measured the voltage on the tubes and definitely there was something wrong on tube 7 6SN7GT

I changed the tube (I love Barcelona, you can find just about anything here)

Et voilą! Now the smeter moves happily

Thank you guys.
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