Troubleshoot Viking Ranger II

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WB2PKR:
Keith, thanks for the link. Nice photos. Hand written notes especially helpful. 73

WB2PKR:
Brief update and some questions...

Gave up on trying to find schematics for the mods as nothing I found was accurate. That said, in addition to links mentioned above, I found these links very insightful…
http://faculty.frostburg.edu/phys/latta/ee/ranger/restoration/restoration.html
http://amfone.net/Amforum/index.php?action=printpage;topic=19981.0
http://www.crompton.com/hamradio/JohnsonRanger/RangerRestoration.html


Decided to just jump in.
In cases where the circuit didnt match the doc (i.e. mods) I just measured components to see if they matched the stated value on the component.

After warming rig up on variac to 115V, I fired it up again. This time after a few minutes, I heard a pop and saw some smoke. Using my nose it wasnt hard to find a smoked R13 (drive pot).
I ordered two replacements (ya never know), and while waiting for the parts to arrive I put some fixed ceramics in its place and continued to troubleshoot. I also removed the 6146 and put a plastic bag over the plate connections.

I then checked voltages and resistances on page 20 & 21 in the ranger manual which lead me to issues with the buffer/multiplier circuits.  Replaced a few shorted caps (C24, C33 & C34) and a few resistors way out of whack (R11, R44). After hitting the wall, I “phoned a friend” and “we” realized that although V4 tested OK on tube tester, it was not working. (The scope is invaluable for this kind of work. I never used one prior to this project and with the help from Elmer, we quickly found the culprit)
We also noticed that the keyer tube , V14 was apparently replaced with a 12AX7A as opposed to the stock 12AU7. Still not sure if that was a mistake or if someone put the higher output amp tube in on purpose. (Anybody?) Regardless, I replaced it with a 12AU7 and I replaced the 6CL6 V4.

With replacement pot installed. she fires up nicely now. 40W carrier into dummy load. 75W+ with audio on peaks.
On 160, the audio is very clean, warm and wide with D104.  Pretty much same on 40. On all other bands, there is a very loud hum or buzz.

I temporarily moved the screen voltage mod pot from in front of the crystal socket and I rewired the crystal socket to the switch so I could check with crystals instead of VFO. No change. bad hum.

Could it be the filament bad grounds as Timtron suggests? If so, why are 160 and 40 so clean? I will reground all the filaments as per Tim. As well as the replace the filament terminal strip mounting rivets with screws, nuts and star washers, but if it was a filament ground issue, why is audio on 160 and 40 so clean? Any other things to check?

OK, thats all for now… Back to the bench…

WD4DMZ:
Good info. I'm following this as I picked up an R2 about 6 weeks ago. Fortunately un modified and so far functioning well.

As the drive pot may become an issue, where did you order them from? Part #?

Thanks, Rich

WB2PKR:
Digikey

KB2WIG:


You may wish to take some of the stress off of the drive pot.... there is a solod state method on  the amwindow site or use some added resistance.

AD5X has a Ranger restoration  using a 5K 5 Watt and a 7.5 K 5 Watt modification in conjunction with the pot... check it out and leave your drive pot worries behind. Do it for the children.

KLC

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