[Hammarlund] Re-Capping HQ-180A - Some Questions

[jm]

Hi guys,

I joined the forum several months ago and this is my first post. So I take
the opportunity to greet all members.

Regarding Steve's questions, I had the same problem. On February the
multi-capacitor filter broke and I bought the Hamfest's kit.
To my surprise, my 180a was not according to the manual schematics. The old
c82 capacitor   had only three sections: 80, 40 and 20 mf , 450v
(the Hamfest has 4 sections, 65,45,45 at 450v and 45 mfd/50v)

After some test, I decided to use the 65, 45 and 45 sections of the Hamfest
capacitor to substitute the older one. I used the parts rated as 450v.
The 45 mf/50 remained unused (if used, the 1.5 kohm resistor attached goes
hotter and hotter until it is charred).

The receiver has been working properly since then.

Regards and sorry for my English.

Jose EA8DCP






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El sáb., 13 jul. 2019 a las 22:57, Kenneth G. Gordon (<
kgordon2006 at frontier.com>) escribió:

> On 13 Jul 2019 at 14:33, Steve Reed wrote:
>
> > Hi all -- I've got a HQ-180A here and and started the re-capping process.
> > The replacement power supply filter capacitor that I ordered from
> > Hayseedhamfest is rated: 65-45-45 (at 450v) and then there's a fourth pin
> > on the can rated 45mfd at 50v.  The ACTUAL filter capacitor on my
> HQ-180A,
> > however, is rated 80-40-20 (450v) and there is no fourth pin.
>
> Hmmm....that must be an early '180...
>
> >  To add to
> > the confusion (and just to make it hard for me to trace a lot of this
> out),
> > the only manual I have for a HQ-180A identifies the filter capacitor
> (C82),
> > as a 60-40-40-40 at 450v.
>
> No. That voltage rating is wrong. It MAY BE what is shown on the can, but
> according to the
> schematic diagrams and the parts lists I have here, that cap is C-82A, 60
> MFD at 400 VDC,
> C-82B, 40 MFD at 400 VDC, C-82C, 40 MFD at 350 VDC, and C-82D 40 MFD at 25
> VDC.
>
> Also, remember that those old caps were speced at something like
> +20%/-100%, so the
> Hayseed cap should work perfectly in that service.
>
> >  So this is wandering all over the place.  So, a
> > couple of questions:
> > 1 - Is that Hayseedhamfest cap a direct replacement regardless of the
> > difference in the ratings?
>
> Pretty much so, yes.
>
> > 2 - Does anyone have a schematic for the version of the HQ-180A I have?
> I
> > realize there were many different production versions.
>
> Well, I have two schematics on different '180As here, both have the 4
> section cap listed,
> and none have a 3 section cap.
>
> In almost every receiver I have dealt with in the past 63 years, that
> fourth pin and cap is the
> cathode bypass cap for the audio output stage.
>
> Your receiver MAY have a separate individual cap for that purpose. You
> will have to
> examine the receiver closely around the audio output stage (6AQ5?) to see
> if there is an
> electrolytic cap of around 25 to 50 MFD connected from the cathode, pin 2,
> to ground.
>
> Usually, these caps are rated at something like 25 to 50 VDC and 25 to 50
> MFD.
>
> Ken W7EKB
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