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 Post subject: Issues with Hammarlund HQ170
PostPosted: Jan Mon 23, 2017 8:10 pm 
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I have two issues with my Hammarlund HQ170.

The first one is that it moves off frequency very rapidly when receiving strong signals. So rapidly that CW sounds chirpy with it but not with my other receivers. It sounds chirpy initially and then the receiver moves so far off that the CW can not be heard until retuned.
I have a Viking Ranger II and Johnsone T/R switch with switch connected to both Ranger II and Hammarlund. The issue occurs when connected to this, and when connected to seperate antenna.

The second issue has caused me to stop using the Hammarlund Receiver until I can sort it. I first noticed it when I moved the radio slightly while it was turned on. The chassis is live. No large current flows (a tickle) but there is 170V on the chassis compared to shack ground. I suspect the large smoothing capacitors. I attempted reforming them by applying low voltage for about 24 hrs each time via a variac pausing for a day and repeating but it seems to have made little difference so far. If I replace them with modern electrolytics I'd like it to look like the originals.

Any comments or suggestions for both issues? Both make the receiver unusable for the purpose I intended which is Rx for my Viking Ranger II transmitter.

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Last edited by vk4mdx on Jan Mon 23, 2017 9:09 pm, edited 1 time in total.

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 Post subject: Re: Issues with Hammarlund HQ170
PostPosted: Jan Mon 23, 2017 8:39 pm 
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Is the HQ170 setup with a 2 wire or a 3 wire AC plug? Is the chassis properly grounded to the main? Line and neutral properly run? Alan


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 Post subject: Re: Issues with Hammarlund HQ170
PostPosted: Jan Mon 23, 2017 9:11 pm 
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The HQ170 has the original US mains chord which is a two conductor chord. It is connected to a variac delivering 110V from 240V mains. There is no earth from radio to variac. I suspect it would trip the RCD if I earthed to mains but I have not tried.

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Last edited by vk4mdx on Jan Mon 23, 2017 9:42 pm, edited 1 time in total.

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 Post subject: Re: Issues with Hammarlund HQ170
PostPosted: Jan Mon 23, 2017 9:41 pm 
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Joined: Nov Thu 07, 2013 3:29 am
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Location: Leesburg, Virginia
Mine had some voltage on the chassis. Didn't find anything singular. Measured much less with a VOM vs VTVM or DMM. Replaced the supply caps. Put a 3-wire grounded cord on it. Figured one way or another it would either work or blow up. So far it's been working.

Anything here with a metal chassis (exposed) that I'm going to use regularly I ground the chassis.

As to the other problem I haven't used this one enough to comment.

Good luck.

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 Post subject: Re: Issues with Hammarlund HQ170
PostPosted: Jan Mon 23, 2017 9:44 pm 
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W0MPM wrote:
Mine had some voltage on the chassis. Didn't find anything singular. Measured much less with a VOM vs VTVM or DMM. Replaced the supply caps. Put a 3-wire grounded cord on it. Figured one way or another it would either work or blow up. So far it's been working.

Anything here with a metal chassis (exposed) that I'm going to use regularly I ground the chassis.

As to the other problem I haven't used this one enough to comment.

Good luck.


What did you replace the caps with? I am pretty sure that if I used a 3 wire chord now I would trip the RCD.

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 Post subject: Re: Issues with Hammarlund HQ170
PostPosted: Jan Mon 23, 2017 10:04 pm 
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Location: Costa Mesa, California
https://hayseedhamfest.com/collections/hammarlund

The above link is one company that offers specific capacitor cans for select radio models. I usually re-stuff the original can or disconnect and add capacitors underneath the chassis. The paper caps in these radios also go bad with time and start leaking. I would replace the power cord with a three wire type, replace the line caps with safety caps--after the switch on the hot side, switch the hot wire, and add an inrush limiter (themister CL-60 type). I always make the fuse the first thing the hot sees when it enters the radio. Your problem with drifting sounds harder to diagnose. Is it for all bands? Does it happen on the Am position? I know it would be harder to tell, but it would eliminate the BFO as the culprit.

Norm

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 Post subject: Re: Issues with Hammarlund HQ170
PostPosted: Jan Mon 23, 2017 10:11 pm 
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Norm Johnson wrote:
https://hayseedhamfest.com/collections/hammarlund

The above link is one company that offers specific capacitor cans for select radio models. I usually re-stuff the original can or disconnect and add capacitors underneath the chassis. The paper caps in these radios also go bad with time and start leaking. I would replace the power cord with a three wire type, replace the line caps with safety caps--after the switch on the hot side, switch the hot wire, and add an inrush limiter (themister CL-60 type). I always make the fuse the first thing the hot sees when it enters the radio. Your problem with drifting sounds harder to diagnose. Is it for all bands? Does it happen on the Am position? I know it would be harder to tell, but it would eliminate the BFO as the culprit.

Norm


Hi Norm

I have replaced all caps other than the ones mentioned. Thanks for the link I will look into the most aesthetic solution to replacing these. I will do some more research regarding the drifting. it has been a long time since I used it or the Viking on AM, though that was the original desire. I tend to use for CW now.

Kimberly

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 Post subject: Re: Issues with Hammarlund HQ170
PostPosted: Jan Mon 23, 2017 10:50 pm 
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Location: Roslyn,Pa 19001
Hi,
In regards to the drift issue I'd have a look at the 0B2 tube and check to see if it's glowing purple inside (as it should). You can use your Icom to have a listen to two conversion oscillators and bfo to hear what is drifting. If you turn the avc off or turn the rf gain down a bit does it get better?
http://bama.edebris.com/manuals/hammarlu/hq170/
GLYL

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 Post subject: Re: Issues with Hammarlund HQ170
PostPosted: Jan Mon 23, 2017 11:11 pm 
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Location: Monterey California USA
The main filter capacitors have nothing to do with the perceived issue of AC on the chassis. Changing them for that reason will be a waste of money. Unless they show excessive leakage and high ESR, you could leave them alone for the moment.

The HQ-170 has two .01 mfd bypass capacitors connected from each side of the AC line input to the chassis. C83 and C84. If you don't ground the chassis or use a 3 wire cord to do so, there is the possibility of getting a slight shock should you touch the chassis and something else that is grounded. It's just leakage through one of those capacitors. A digital meter will show nearly line voltage on the chassis while an older analog one will show less or sometimes very little. Ideally they should be replaced with safety types but the leakage will still be there, to some extent.

Yes, putting a 3 wire cord on a receiver or grounding the chassis will often trip a GFI receptacle (what is an RCD?) The solution is to not use one feeding the equipment. If you are in a nanny state that dictates that every receptacle be GFI, then you will have to remove the bypass capacitors in the receiver. Try reversing the line cord in the socket first to see if that helps any. This is true of most receivers of the era including things like the Collins R-390 and 390A.

The 170 will drift like crazy when first powered up. Leave it on for at least half an hour and see if it still does this. The 170A has a separate transformer that leaves the oscillator tube lit all the time to reduce or eliminate this issue. My pet theory as to what is happening these days is that the temperature compensating capacitors which are supposed to cancel drift have failed with age and the drift is worse now. I suspect some chemical deterioration in whatever the compensating material is. Simplest solution is to let the set warm up for some time, although I know this is a nuisance.
Voltage regulation also plays a part but if the VR tube is lit, that part is most likely OK.

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 Post subject: Re: Issues with Hammarlund HQ170
PostPosted: Jan Tue 24, 2017 1:05 am 
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You need to be very, very careful using a variac or any autotransformer to step down voltage. If done improperly you can end up with a huge potential to ground. See picture below.

I suspect you're however getting leakage thru the line filter caps. Just ground the chassis to the outlet ground and you should be fine - but beware of the autotransformer issue above.

Image


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 Post subject: Re: Issues with Hammarlund HQ170
PostPosted: Jan Tue 24, 2017 1:25 am 
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Location: Sayreville, NJ 08872
vk4mdx wrote:
I have two issues with my Hammarlund HQ170.

The first one is that it moves off frequency very rapidly when receiving strong signals. So rapidly that CW sounds chirpy with it but not with my other receivers. It sounds chirpy initially and then the receiver moves so far off that the CW can not be heard until retuned.
I have a Viking Ranger II and Johnsone T/R switch with switch connected to both Ranger II and Hammarlund. The issue occurs when connected to this, and when connected to seperate antenna.
<cut>


You can try a different 6C4. Not all 6C4's seem to be equal in performance and drift. The HQ-170 has known AVC issues that were documented by Hammarlund in service addenda. Strong signals could drive the AVC voltage enough to pull the BFO or mixers off frequency. Try backing off on the RF gain control on strong signals.

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 Post subject: Re: Issues with Hammarlund HQ170
PostPosted: Jan Tue 24, 2017 2:17 am 
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Location: USA
It should not be difficult to determine if variation in B+ power is the source of the issue. Measure the output at the voltage regulator tube to see if you get the right reading. I think a properly functioning OB2 should be at ~106-110V.

I think the issue with having line voltage on the chassis is more serious and should be resolved first before you move on to anything else.

As Geoff said, the issue is likely not the smoothing/filter capacitors. The mains line voltage is exposed to the chassis only via a pair of 0.01 mfd capacitors (C83, C84); there should not be any significant voltage on the chassis. Check for a physical short.

If everything is working correctly, grounding the chassis should not trip RCD.

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 Post subject: Re: Issues with Hammarlund HQ170
PostPosted: Jan Tue 24, 2017 6:14 am 
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Geoff Fors wrote:
T
The HQ-170 has two .01 mfd bypass capacitors connected from each side of the AC line input to the chassis. C83 and C84. If you don't ground the chassis or use a 3 wire cord to do so, there is the possibility of getting a slight shock should you touch the chassis and something else that is grounded. It's just leakage through one of those capacitors. A digital meter will show nearly line voltage on the chassis while an older analog one will show less or sometimes very little. Ideally they should be replaced with safety types but the leakage will still be there, to some extent........

Yes, putting a 3 wire cord on a receiver or grounding the chassis will often trip a GFI receptacle (what is an RCD?) The solution is to not use one feeding the equipment. If you are in a nanny state that dictates that every receptacle be GFI, then you will have to remove the bypass capacitors in the receiver. Try reversing the line cord in the socket first to see if that helps any. This is true of most receivers of the era including things like the Collins R-390 and 390A.

The 170 will drift like crazy when first powered up. Leave it on for at least half an hour and see if it still does this. The 170A has a separate transformer that leaves the oscillator tube lit all the time to reduce or eliminate this issue. My pet theory as to what is happening these days is that the temperature compensating capacitors which are supposed to cancel drift have failed with age and the drift is worse now. I suspect some chemical deterioration in whatever the compensating material is. Simplest solution is to let the set warm up for some time, although I know this is a nuisance.
Voltage regulation also plays a part but if the VR tube is lit, that part is most likely OK.



Starting with the "drift." I would not call it drift when it happens in milliseconds and results in a CW tone chirping, that is something more significant or much different to "drift" and I always warm the set up for ages- not an inconvenience at all. I don't suspect temperature compensating capacitors at all. I suspect some other issue but not sure where to start but that AVC is suspicious.

As mentioned previously, I did replace all other caps including the two mentioned so seems "the leakage will be there to some extent" is the situation. An RCD is a residual current device. I've tried flipping the AC plug. I am in Australia, all new buildings must have RCDs. My apartment building is less tan 2 years old. What is a GFI?

New voltage regulators and lots of spares tried.

I will try replacing mains chord and see if I trip the RCD.

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 Post subject: Re: Issues with Hammarlund HQ170
PostPosted: Jan Tue 24, 2017 6:18 am 
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AJJ wrote:
It should not be difficult to determine if variation in B+ power is the source of the issue. Measure the output at the voltage regulator tube to see if you get the right reading. I think a properly functioning OB2 should be at ~106-110V.

I think the issue with having line voltage on the chassis is more serious and should be resolved first before you move on to anything else.

As Geoff said, the issue is likely not the smoothing/filter capacitors. The mains line voltage is exposed to the chassis only via a pair of 0.01 mfd capacitors (C83, C84); there should not be any significant voltage on the chassis. Check for a physical short.

If everything is working correctly, grounding the chassis should not trip RCD.



I do get the correct reading. The issue has existed since I acquired the set some years ago and I went over the whole thing and checked all in the service manual and gave it an alignment. Voltages were correct then and I suspect now and the chirp problem has been there all along.

C83 and C84 replaced with new at that time.

I will ground the chassis and see what happens with the RCD

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 Post subject: Re: Issues with Hammarlund HQ170
PostPosted: Jan Tue 24, 2017 6:19 am 
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w3jn wrote:
You need to be very, very careful using a variac or any autotransformer to step down voltage. If done improperly you can end up with a huge potential to ground. See picture below.

I suspect you're however getting leakage thru the line filter caps. Just ground the chassis to the outlet ground and you should be fine - but beware of the autotransformer issue above.

Image



No choice. I am certainly not going to modify it for 240V. Why do the yanks not label the plug? How do they avoid reversal of N and A?

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Last edited by vk4mdx on Jan Tue 24, 2017 6:24 am, edited 1 time in total.

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 Post subject: Re: Issues with Hammarlund HQ170
PostPosted: Jan Tue 24, 2017 6:22 am 
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manualman wrote:
vk4mdx wrote:
I have two issues with my Hammarlund HQ170.

The first one is that it moves off frequency very rapidly when receiving strong signals. So rapidly that CW sounds chirpy with it but not with my other receivers. It sounds chirpy initially and then the receiver moves so far off that the CW can not be heard until retuned.
I have a Viking Ranger II and Johnsone T/R switch with switch connected to both Ranger II and Hammarlund. The issue occurs when connected to this, and when connected to seperate antenna.
<cut>


You can try a different 6C4. Not all 6C4's seem to be equal in performance and drift. The HQ-170 has known AVC issues that were documented by Hammarlund in service addenda. Strong signals could drive the AVC voltage enough to pull the BFO or mixers off frequency. Try backing off on the RF gain control on strong signals.


I will try what you suggest when I get a chance- have stacks of 6C4's and changed them several times already trying to resolve this so I doubt they are the cause. I recall from earlier testing that backing off RF gain helped a tiny bit but not significantly and frankly is not a workable solution when in a CW QSO The strong signal is mine, then I need to turn up to hear the other party/s..not really a good solution - I suspect the horrible AVC is doing something it should not.

Will do more testing when I solve the voltage on the chassis issue but suggestions welcome especially from those with specific knowledge of the AVC. Can I get rid of it...even temporarily for a test?

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 Post subject: Re: Issues with Hammarlund HQ170
PostPosted: Jan Tue 24, 2017 7:09 am 
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Location: USA
Quote:
Why do the yanks not label the plug? How do they avoid reversal of N and A?


We do, but not when HQ-170 was originally built.

Please keep up posted as you make progress on the radio :)

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 Post subject: Re: Issues with Hammarlund HQ170
PostPosted: Jan Tue 24, 2017 7:19 am 
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vk4mdx wrote:
What is a GFI?
Hi Kimberly,

A GFCI (properly) is a Ground Fault Circuit Interrupter.

It compares the current flowing in the hot and neutral conductors.
If they are not equal (within a narrow tolerance) it opens the circuit, like a fuse.

This is based on the assumption that if current in the hot exceeds current in the neutral, the missing current must be flowing to ground. Probably a reasonable assumption in the general case.

vk4mdx wrote:
Why do the yanks not label the plug? How do they avoid reversal of N and A?
Back when AC service first came into use, all radios were transformer-powered, so the sense of hot and neutral relative to ground was not of any importance.
Neither side of the line connected to the radio's chassis, which was grounded.

Later (1950s) when transformerless radios came on the scene, one side of the line connected to the chassis without regard for its sense. That did not matter because the entire chassis was completely isolated from the operator by plastic or rubber insulation.

- Leigh

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 Post subject: Re: Issues with Hammarlund HQ170
PostPosted: Jan Tue 24, 2017 8:39 am 
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Leigh wrote:
vk4mdx wrote:
What is a GFI?
Hi Kimberly,

A GFCI (properly) is a Ground Fault Circuit Interrupter.

It compares the current flowing in the hot and neutral conductors.
If they are not equal (within a narrow tolerance) it opens the circuit, like a fuse.

This is based on the assumption that if current in the hot exceeds current in the neutral, the missing current must be flowing to ground. Probably a reasonable assumption in the general case.

vk4mdx wrote:
Why do the yanks not label the plug? How do they avoid reversal of N and A?
Back when AC service first came into use, all radios were transformer-powered, so the sense of hot and neutral relative to ground was not of any importance.
Neither side of the line connected to the radio's chassis, which was grounded.

Later (1950s) when transformerless radios came on the scene, one side of the line connected to the chassis without regard for its sense. That did not matter because the entire chassis was completely isolated from the operator by plastic or rubber insulation.

- Leigh


RCD and GFI are the same thing then

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 Post subject: Re: Issues with Hammarlund HQ170
PostPosted: Jan Tue 24, 2017 8:46 am 
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vk4mdx wrote:
RCD and GFI are the same thing then

Except that a "GFI" does not exist.

The device under discussion is a GFCI.

- Leigh

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