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Ranger - HQ-170A VFO Issue




 
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Author Topic: Ranger - HQ-170A VFO Issue  (Read 1229 times)
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WE1X
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« on: January 28, 2020, 09:57:38 AM »

Need some advice from the seasoned Ranger ops.

I recently acquired a Ranger 1 with PTT and updated electrolytics and a few other caps. I went ahead and did the usual clean-up with deoxit, switches, etc. The VFO on 160 and 80m appears to be spot on when transmitting per 3rd party receivers.  40m is way off, but not a primary concern at this point.

So here is the problem. When I turn on the Ranger and Hammarlund and tune the VFO all is fine. The Zero beat function, Tune function, etc. work as shoot. I do a final tune up and all is good.

However, after about 10 minutes I hear a very loud stuttering coming from the Hammarlund and then a very loud hum to the point that it obliterates any signal on the receive frequency. Worse when the Ranger is in the PHONE position, but still a problem when switched to TUNE or STANDBY.  When I move the Ranger's VFO off frequency the noise abates but does not disappear until it's way off frequency.

It appears something is breaking down as the Ranger warms up. Any idea where I should begin to look or any major known culprits?

Thanks,

Harry
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WE1X
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« Reply #1 on: January 28, 2020, 09:58:46 AM »

Let me add that other receivers in the rack pick up the noise quite well with no connection to the Ranger.

Harry
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N3GTE
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« Reply #2 on: January 28, 2020, 11:44:30 AM »

I would remove V1 and V2 insert an 80mtr xtal in the appropriate xtal socket and see if the problem is still there. If it isn't I'll bet it's R-3 going.

GL
Terry N3GTE
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WE1X
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« Reply #3 on: January 28, 2020, 12:35:39 PM »

Terry,

Thanks. Much appreciated.
Any tips on how to gain access to the VFO chassis?

Harry
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N3GTE
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« Reply #4 on: January 28, 2020, 01:22:43 PM »

Nope Had a Valiant yrs ago that was cursed and gave up on Johnson stuff built after the VKII.

Terry
ps found this from Wireless Girl  https://wireless-girl.com/Projects/AMTransmitters/JohnsonVFOresistor.html
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nq5t
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« Reply #5 on: January 28, 2020, 01:43:26 PM »

Terry,

Thanks. Much appreciated.
Any tips on how to gain access to the VFO chassis?

Harry

My somewhat dim recollection is the one of the side panels (left?) will come off relatively easily.  There may be nuts under the chassis on screw studs that have to be removed.  I think the entire VFO cover can be removed and lifted out, and is attached with nuts under the chassis, and screws on top.  But I wouldn't recommend it if you can get to the tubes with just the side panel off.  At least some of the under-chassis nuts are in crowded locations and really hard to get to.  The really fun part is getting the fiber shaft extensions on the adjustment caps lined up and back in place if you go so far as to have to remove the top cover :-)

Its been several years since I've worked on a Johnson rig with that VFO housing so buyer beware.
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KB2WIG
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« Reply #6 on: January 28, 2020, 10:11:11 PM »



The following may be of interest

https://www.frostburg.edu/personal/latta/ee/ranger/restoration/restoration.html#vforepair

KLC
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What? Me worry?
WE1X
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« Reply #7 on: January 29, 2020, 08:17:26 AM »

All,

Thanks for the links and suggestions. Have been doing web searches and reading up on this. With the PTT fixture installed removal of the VFO chassis side panel is going to be a bit of a chore. But it is what it is. BTW I think Wireless Girl's images are for the Valiant as the Ranger's V1 and V2 tubes are on the left side not the right.

Thanks again,

Harry
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KD1SH
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« Reply #8 on: January 29, 2020, 09:10:11 PM »

  I did mine a while back; not a huge deal, really.  Requires some patience and good old steady-handed manual dexterity, that's all.  I left my new resistor inside the VFO enclosure, though some recommend relocating it outside.  My reasoning being that it's not so much heat that's the enemy of VFO stability, but rather unsteady heat.  YMMV, as they say.

All,

Thanks for the links and suggestions. Have been doing web searches and reading up on this. With the PTT fixture installed removal of the VFO chassis side panel is going to be a bit of a chore. But it is what it is. BTW I think Wireless Girl's images are for the Valiant as the Ranger's V1 and V2 tubes are on the left side not the right.

Thanks again,

Harry
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WE1X
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« Reply #9 on: February 12, 2020, 07:01:13 AM »

Well I went in the Ranger this weekend to look at the resistor and test the OA2.  Both looked fine and no evidence of heat damage, etc.  Replaced the resistor with what I had on hand (3W 18K) reassembled the VFO housing and unfortunately this did not solve the problem. I still have overwhelming hum  with the Ranger in Phone position and tuned to the receiver. Moving the function switch to Tune, Standby reduces the hum / noise level but still overwhelming. Will dig around for some crystals to  test whether this is VFO specific or something else. In the meantime, if anyone has any other suggestions I would greatly appreciate it.

Thanks,

Harry
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N4DJ
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« Reply #10 on: February 25, 2020, 09:12:56 AM »

I know its a bit hard to get into the Ranger VFO. I changed my 18K, R3 once!  Did you try changing tubes while in there? My first thought is always change the tube because its easy and lots of times it fixes the problem without thinking too hard!
Don
N4DJ
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WD4DMZ
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« Reply #11 on: March 03, 2020, 04:22:19 PM »

I have a largely unmolested Ranger 2 that does this. With the antenna connected there is a very slight buzz on the VFO frequency that I pick up in the receiver. Not enough to be a a problem but enough to use to spot the receiver even in the standby mode.

This morning I connected the R2 to three different receivers and the noise appeared in all three. The receivers were an HQ145x, HQ100A and an SX71. This was actually helpful with the SX71 as it has no calibrator and it enables me to set the dials up. I use a cheap Chineseeum digital freq meter to set the R2 and after a 30 minute warmup the R2 stays on frequency +/- 10 Hz.

If I remove the antenna from the R2 output the small hum becomes a roar and almost overpowers the receiver. So, the noise comes directly from the VFO. When on a crystal position there is no noise at all.

When transmitting there is apparently no noise on the carrier as when I ask about it no one can detect it.

Since it does not pose a problem in use I will just leave it alone. This is the only Ranger I have ever owned so do not know if it is typical of them.

Rich
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W3DBB
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« Reply #12 on: March 04, 2020, 07:19:56 AM »

Had the receiver hum too. Didn't matter what receiver; the receiver was not the problem. It was the adjustment on the grid-block keying module that is not present on earliest versions of the first Ranger. Johnson added it to the back of the front panel left of center toward the top?- on subsequent versions. Easy to get to. Sorry I'm relying on memory here. I backed the adjustment down until the VFO sound disappeared from the receiver output. An elderly VE3___ from Bowmanville told me if I turned it down further the CW note would "ring like a bell". Never tried that one but have a homebrew single 6146 CW TX here that rings that way. It sounds pretty cool! Don't have the Ranger manuals in front of me and haven't run the Ranger in over 20 years so sorry for the lack of specificity. But look around- you'll find it- unless it's an early original Ranger that has not been modified for grid-block keying.

-Doug
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WD4DMZ
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« Reply #13 on: March 04, 2020, 09:42:50 AM »

Great info. Thanks.

Rich
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WE1X
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« Reply #14 on: March 07, 2020, 03:27:49 PM »

Guys,

Sorry I haven't replied but been under the WX for past few weeks.

V1 and V2 were tested and replaced when I went into the VFO.

Doug, thanks for the tip. I believe it's R39 on the PTT fixture. Will give that a look.

Thanks,

Harry WE1X
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