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Viking II dumpster find




 
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k7mdo
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« Reply #25 on: April 24, 2016, 11:04:16 PM »

OK, back from Machu Pichu and an Amazon cruise in Peru.... and yes, I did swim in the river and the next day we fished for and caught piranhas in nearly the same location.  Seems they don't eat hams!?!

On return I found a Hallicrafters SX-111 set on my bench which is superseding the Viking II dumpster repair for a while as I need a matching AM rig to complement my HT-37. 

It needs little repair but will probably set me back a week or so.

It does have a 'new wrinkle' not seen before by me and that is what appears to be a chassis heater in the undercarriage.  8 watt 2000 ohm heater element across the line along with the transformer.  Seems like a clever idea to help stabilize the temp drift of the receiver. 

Any other guess, and have you seen it before?

73, Tom
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k7mdo
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« Reply #26 on: April 27, 2016, 03:44:59 PM »

OK on no response to previous post.....  I have worked on the SX-111 for a couple of days and understand it better.  Interestingly enough the "chassis heater" is just that and is on any time the line cord is plugged into the wall socket.  It is separately fused (1/4 ampere) and is positioned under the IF cans, mid receiver.

Probably the most  (or least) interesting part is the low quality of assembly of the entire radio.  I have been working on early Hammarlunds and never seen as poor a wiring job.  The wires are so poorly dressed and the solder "globs" are so frequent you just want to rebuild the entire radio.  I was not aware of the circumstances surrounding Hallicrafters in the early '60's but this receiver is a poor advertisement for their expertise. On the other hand, it played when originally brought to me even with three incorrect tubes in place.  The 6BY6's were replaced with 6BE6's, etc....  I have a couple of the correct tubes coming and can't wait to hear the difference.

Will get back in the Viking II as soon as the tubes arrive.  I have thought a lot about the Viking since leaving it for the duration of my vacation in Peru.  I am going to start over to be sure there isn't some short that the ohm meter does not find that might be causing the "frying" transformer sounds. Still not looking forward to grafting in a new low voltage transformer.... but I have a spare so...

73, Tom
 




* Machu Picchu 2 e.jpg (625.07 KB, 1296x972 - viewed 118 times.)
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KA2DZT
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« Reply #27 on: April 27, 2016, 03:55:22 PM »

OK on no response to previous post.....

73, Tom
 

We're still in shock that you survived the swim in the Amazon.

Fred
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Pete, WA2CWA
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« Reply #28 on: April 27, 2016, 04:17:13 PM »

There were three versions of the SX-111. Early version had 12 tubes; later version added a crystal calibrator (13 tubes); even later version added a product detector (14 tubes).
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« Reply #29 on: April 27, 2016, 05:55:23 PM »

My Hallicrafters SX101A has the heater in it across the line, so it must have been somewhat common in that era. Though mine seems to be located under the front end oscillator circuit.

Regarding the frying sound in the V2, that is what I heard before the rf choke popped. But, that was with the HV switch on to the 6146 plates.

By the way, if still agreeable, I would sure like to get a spare rfc from the cannibalized set. I'll send you a couple $$ to defray shipping.

Thanks, Rich
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k7mdo
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« Reply #30 on: April 27, 2016, 11:08:35 PM »

Rich, I would gladly give you one but the accessory socket was missing along with the chokes... the only choke I have is the fried one on the big
plate  choke... so, I don't have a spare either.

Tom
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WD4DMZ
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« Reply #31 on: April 27, 2016, 11:23:30 PM »

Thanks for looking. I'll head to Mouser.

From the great audio reports I am getting using a non amped D104 on my V2 I am sure reviving your V2 is worth the effort.

Good luck, Rich
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k7mdo
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« Reply #32 on: May 02, 2016, 05:17:53 PM »

Well, probably the reason the two Vikings were in a dumpster is that both have bad low voltage transformers...  I am going to look into a rewind but if it gets over $100 then the units become more parts ponies than I thought.

I guess the good news is that I have a working Viking II CD that probably will eventually need a part from one of these....  not sure yet what I am going to do.

I got the Hallicrafters SX-111 Mark 1 up and integrated into the shack... it is actually pretty decent and the drift is very minimal.  The learning experience on it was that on close examination the power transformer on it had been replaced with one that was marginal for the current drain, especially for the 6.3 VAC winding... it tended to warm up too much trying to light the number of tubes.... so, into my "warehouse" of leftovers and I found a small filament transformer and I grafted it into the set and "unloaded" part of the main transformers filament burden. Time will tell if I have done enough.

Rich, if I decide to part out the Vikings, I will definitely have a spare choke or two...  73, Tom


 
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w4bfs
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« Reply #33 on: May 02, 2016, 07:40:18 PM »

Well, probably the reason the two Vikings were in a dumpster is that both have bad low voltage transformers... 

This could have been prevented by a seperate primary fuse for the low voltage transformer...

Please take note ALL boatanchor owners ... this problem is real for most transmitters ... just to save the cost of a fuse !  Angry Huh Cry
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« Reply #34 on: May 02, 2016, 11:24:42 PM »

Another way to off-load some current would be to replace the 5Y3 with a pair of 1N4007 diodes. No more 5V filament current draw and a lot less heat in the cabinet to boot.

Visit QRZ and my photo shows the V2 with four different receivers I rotate in. The SX42 sounds the best with the R42 reflex speaker but the HQ180 offers the best selectivity, if not very good audio.

Rich
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« Reply #35 on: May 03, 2016, 10:36:42 AM »

Well, probably the reason the two Vikings were in a dumpster is that both have bad low voltage transformers...  I am going to look into a rewind but if it gets over $100 then the units become more parts ponies than I thought.

I guess the good news is that I have a working Viking II CD that probably will eventually need a part from one of these....  not sure yet what I am going to do.

I got the Hallicrafters SX-111 Mark 1 up and integrated into the shack... it is actually pretty decent and the drift is very minimal.  The learning experience on it was that on close examination the power transformer on it had been replaced with one that was marginal for the current drain, especially for the 6.3 VAC winding... it tended to warm up too much trying to light the number of tubes.... so, into my "warehouse" of leftovers and I found a small filament transformer and I grafted it into the set and "unloaded" part of the main transformers filament burden. Time will tell if I have done enough.

Rich, if I decide to part out the Vikings, I will definitely have a spare choke or two...  73, Tom


 

I don't understand throwing away a classic transmitter due to a bad transformer or choke.

There are transformer manf. out there who have transformers spot on or close to the original specs such as EDCORUSA, Hammond, etc.

A bit of imagination and slight modification of the chassis (the drilling of holes in slightly different positions) can save them.

I am glad you found them and are willing to bring them back to life.

Phil - AC0OB
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« Reply #36 on: May 03, 2016, 11:09:35 AM »

Dealing with failed transformers & boatanchors is a fact of life. Gonna happen. Have Gary, WZ1M, rewind your transformer. It will be better than new. Anything found in another old Viking II will have the same issues, "old".

Craig,
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AJ1G
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« Reply #37 on: May 03, 2016, 08:45:36 PM »

Well, probably the reason the two Vikings were in a dumpster is that both have bad low voltage transformers... 

This could have been prevented by a seperate primary fuse for the low voltage transformer...

Please take note ALL boatanchor owners ... this problem is real for most transmitters ... just to save the cost of a fuse !  Angry Huh Cry

As I noted in my thread on using the Rockland 5100 synthesizer as a VFO to drive  my newly acquired Viking II, my original V II transmitter also lost its LV transformer.  I had turned the set on to warm up while I was finishing up mowng the lawn,  about ten minutes later, there was a thick pall of tarry smoke in the basement shack, I distinctly remember that a bare 60 watt light in the basement overhead was barely visible through the smoke.

I am going to fuse the LV transformer primary on the new set before I fire it up.  Oops, bad pun....there was smoke once, don't want fire the next time!

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Chris, AJ1G
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« Reply #38 on: March 13, 2017, 11:28:28 PM »

Phil said last year:

I replaced the two caps with 0.047 uF at 2kV for better high frequency response.

Where did you get the caps? I am going to get the chokes from Mauser but they do not seem to have these caps.

Thanks, Rich
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KB2WIG
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« Reply #39 on: March 14, 2017, 12:02:13 AM »



http://www.mouser.com/Passive-Components/Capacitors/_/N-5g7r?P=1z0z819Z1yp7xv5&Keyword=.047+uf&FS=True

Around $3.75 a piece.

Or try RF Parts for 1KV Disk Capacitor, Ceramic, 0.022uf 1000v, Radial Leads     $0.55  double 'em up, and there you ar

https://www.rfparts.com/c203-1kv.html



I didn't look at the application, but, generally, something in the neighborhood will work. Just make sure that the voltage rating for the ckt is OK.
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WD4DMZ
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« Reply #40 on: March 14, 2017, 11:30:21 AM »

Perfect. Thank you.

Rich
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K4RT
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« Reply #41 on: March 14, 2017, 02:51:40 PM »


This could have been prevented by a seperate primary fuse for the low voltage transformer...

Please take note ALL boatanchor owners ... this problem is real for most transmitters ... just to save the cost of a fuse !

Why is the main transmitter fuse on the incoming AC line not enough?  Is the added fuse on the LV xfmr primary to be of a current rating based on normal current drawn at that primary?  Should all xfmrs be fused?  I have seen several web posts through the years advising additional fusing but so far have not seen an explanation.
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« Reply #42 on: March 14, 2017, 05:48:13 PM »

a fair enuff question ....

suppose you have a low voltage transformer to provide something like +300V and filament power... adding it all up lets us assume that It will need to provide 150W of power .... a 1.5 A regular fuse is a good starting point .... nothing unusual here

keep also in mind that if you modify the lv power supply from its stock configuration (such as buck wiring the primary with an unused 5V winding as part of solid stating the lv supply) may remove load from the lv supply

most transformers with EI laminations are roughly 10W per pound .... toroidals are less weight for the same power .... the clamp on ammeter is your friend for good determinatios of actual power levels

back to the original question .... if a 5A line fuse is the only current limiting component in this transmitter and a failure occurs in an separately unfused lv power supply section then it would allow up to 600W of power in that section before it would open up...not good
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Beefus

O would some power the gift give us
to see ourselves as others see us.
It would from many blunders free us.         Robert Burns
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