Zenith 8G005 restore-Redux - Printable Version
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+--- Thread: Zenith 8G005 restore-Redux (/showthread.php?tid=15559)
Zenith 8G005 restore-Redux - klondike98 - 10-19-2016
OK Terry here it comes….again...I know you’ve been waiting for this
I picked up another 8G005 Transoceanic. This one is not quite as good a shape as the one in my previous thread but better in most respect than the parts set I bought. It’s also the earlier 8G005YT version with the 117Z3 rectifier.
[Image: https://www.dropbox.com/s/ln434aepva3d604/zenith8G005-2_01.jpg?raw=1]
[Image: https://www.dropbox.com/s/9bibnrnphvk5ww7/zenith8G005-2_02.jpg?raw=1]
[Image: https://www.dropbox.com/s/hnztlwyyjsgexrh/zenith8G005-2_03.jpg?raw=1]
[Image: https://www.dropbox.com/s/daz9oxg50n175e0/zenith8G005-2_04.jpg?raw=1]
The electrolytic cap (40/20/10 uF ) had been replaced at some time in the past as had the 88 ohm resistor (with a 72 ohm power resistor). Both need replacing. The rubber wiring on this set is not in as good a shape as the earlier set either. I'll need to replace wire in several places and particularly the battery wires. Here are some photos of the battery plug rewire. Its not too hard to pry out the tabs holding the plug wafer face in place, you just need a thin bladed screw driver. Take your time, I imagine it doesn't take much to crack the wafer.
[Image: https://www.dropbox.com/s/ef3q7xgx9meveoo/zenith8G005-2_05.jpg?raw=1]
[Image: https://www.dropbox.com/s/l5k4su8gh4xpj7c/zenith8G005-2_06.jpg?raw=1]
[Image: https://www.dropbox.com/s/23ixpaqathd5qqo/zenith8G005-2_07.jpg?raw=1]
[Image: https://www.dropbox.com/s/0neonqt4tsfpmwt/zenith8G005-2_08.jpg?raw=1]
RE: Zenith 8G005 restore-Redux - klondike98 - 10-20-2016
moving along...the battery wiring is installed and recapping is underway...
[Image: https://www.dropbox.com/s/bzeqt9i0ffxkcn7/zenith8G005-2_09.jpg?raw=1]
RE: Zenith 8G005 restore-Redux - OldRestorer - 10-20-2016
How will you do the batteries?
I have 2 portables that only take batteries and I cant seem to understand how to build them...
Looks good Bob..
Me
RE: Zenith 8G005 restore-Redux - klondike98 - 10-20-2016
This puppy runs on both battery and house power. The battery wires were so bad I had to replace them or risk bare wire shorts but will likely just power it with 120ac. There's a fellow who makes a battery pack for TOs but its pretty pricey at something like $150. We'll see, maybe I'll feel energetic and make something up.
RE: Zenith 8G005 restore-Redux - sam - 10-21-2016
bob
looking good
you can build a battery box
RE: Zenith 8G005 restore-Redux - klondike98 - 10-29-2016
I have finished recapping this radio and am able to hear the local broadcast stations clearly but there is an annoying hum or put-putting in between the local stations. All the voltages on the tubes seem to be in line with what is on the schematic (here's the schematic LINK, ignore the red line highlights).
When I do the first step of the alignment procedure, i.e. modulated 455kc applied to the grid (pin 6) of the 1LC6 converter) with band switch at Broadcast and tuning dial at 60 I can hear the tone but there is also a motorboating sound that is louder than the tone. If I switch the Band Switch to any of the Shortwave bands, the motorboating goes away and I hear a nice clear tone. That should tell me something but I'm not quite sure what. There must be something amiss in the broadcast band portion of the circuit. (I've done the deoxit cleaning on the switch connections with no change.) Any thoughts?
RE: Zenith 8G005 restore-Redux - Radioroslyn - 10-29-2016
Gosh I thought I got rid of you!!!!!!
JUST KIDDING!
Well there is a couple of things we can do to try to see which stage is oscillating that isn't suppose to be.
Plan A Turn on set. Get it motorboating. Place one of your fingers one of the rf or mixer coils. Do this until you get to a coil that stops or changes the motorboating sound. This will give a clue has to which stage is the issue. By touching the coil it detunes it changes it's characteristics hopefully enough to make a difference and change how the circuit is misbehaving.
Plan B Grab a weak 1.4v loctal tube and cut off all of it's pins except for the 2 filament pins. Think it's pins 1 and 8. Probably wouldn't chop up a converter tube there a little harder to come than the others. Since your filament circuit is in series if you remove one tube they all go out. But if you replace one with this tube it will keep the filament circuit in tacked. Use this tube to swap with the rf,mixer, and if tubes to find the motorboating stage.
RE: Zenith 8G005 restore-Redux - Radioroslyn - 10-29-2016
Obtw I hear that Todd Lake is nice this time of the year.....
RE: Zenith 8G005 restore-Redux - klondike98 - 10-29-2016
(10-29-2016, 12:12 PM)Radioroslyn Wrote: Obtw I hear that Todd Lake is nice this time of the year.....
I never thought of it quite that way.....I drive by it all the time...its a tiny little pond next to a capped landfill site...
[Image: https://www.dropbox.com/s/1883kw7exonqwxy/todd.jpg?raw=1]
I'll give plan A or B a try later today....
RE: Zenith 8G005 restore-Redux - sam - 10-29-2016
maybe nice view or for a picnic
I would not go swimming in it
RE: Zenith 8G005 restore-Redux - Radioroslyn - 10-29-2016
(10-29-2016, 02:13 PM)klondike98 Wrote:The perfect place for your motorboat!(10-29-2016, 12:12 PM)Radioroslyn Wrote: Obtw I hear that Todd Lake is nice this time of the year.....
I never thought of it quite that way.....I drive by it all the time...its a tiny little pond next to a capped landfill site...
[Image: https://dl.dropboxusercontent.com/u/54621529/todd.jpg]
I'll give plan A or B a try later today....
RE: Zenith 8G005 restore-Redux - klondike98 - 11-03-2016
So I proceeded with Plan A, placing my finger next to each of the coils,but it did not result in any changes in the putt-putting sound on the broadcast band. I went back and carefully checked the recapping to be sure I didn't make a wiring mistake like last time and everything looked good. The only thing I found was the slide switch on the "Wave Magnet" antenna plug was sticky so I applied some Deoxit and gave it a workout. After firing up the radio the putt-putt sound was gone and I was picking up BC stations. Proceeded to begin alignment and all went well for Broadcast. Switched to the 49Meter band and that also aligned well but when I switched to the 31Meter band I could not hear anything. Going back to the BC band, it was dead also....grumble. Thinking it had to be something in the band switching mechs I went through another round of switch cleaning and to get a better shot as some of the hard to get connections I took off the shield this time. In doing so it seemed that some of the leads on the switch mech were awfully close to the side of the box and when I checked to see if there was continuity between the shield and switch leads.... I got flakey, intermittent readings so I decided there was some shorting going on. A little bending and some electrical tape on the inside of the shield and that problem was solved.
[Image: https://www.dropbox.com/s/69kwkhc50yipwlc/zenith8G005-2_10.jpg?raw=1]
Back to alignment and I was able to align each band now.
After putting it all back together and in the case and taking the set out of the basement it seems to be working on all bands although I get quite a bit more hum and static than I did on the earlier set I did. Once tuned to a strong station,however, its pretty clear. I didn't spend a lot of time cleaning the variable cap...maybe I should.[Image: https://www.dropbox.com/s/ncnf2fw6dorv1it/zenith8G005-2_11.jpg?raw=1]
RE: Zenith 8G005 restore-Redux - sam - 11-03-2016
Looks great
I'll send mine over. Since your on a roll
RE: Zenith 8G005 restore-Redux - klondike98 - 11-03-2016
Thanks sam....
RE: Zenith 8G005 restore-Redux - OldRestorer - 11-04-2016
Looks real nice...
One day I will learn to align radios...
