January 12, 2020 at 5:50 pm #12803
I wanted to tackle the Globetrotter over the winter and started by removing the chassis without incident. Thought I’d start with testing the tubes and ordering all the caps etc. There are 8 tubes total and they are: 5Z3, my tester has no listing for this tube?? (5Z4) is on the list however.
6L7 All 4 of these don’t register on the meter, however, there is no wire connected to the top pins. The tester has a Black and a Red wire with the correct clips, but no instruction which to use. I used neither rather than risk damaging the tubes. Don’t have a next move. Use the Red or Black wire?? (sounds like I’m defusing a bomb)
6F6 tests weak (I thought I would upgrade to a 6V6)
6H6 tests good
6N5 again, no listing for this tube, but I think it’s the magic eye tube and it glowed brightly Green when I plugged the radio in briefly when I first acquired it. Schematic calls for a 6E5 however.
I will go over the parts list and start gathering the caps etc, but I’m stymied as far as what to do with the tubes. I guess I bought a sh*^ty tube tester.
- This topic was modified 2 years, 7 months ago by garykuster.
Attachments:January 12, 2020 at 6:22 pm #12809John GreenlandCVRS Member
The info on a Century FC-2 Tube tester is here.
The code number for the unit is on the bottom.
Perhaps this can help.
VO1 CATJanuary 12, 2020 at 7:15 pm #12817
Already in trouble Pt.2
I just had a closer look at the schematics I downloaded from Radiomuseum and they are unclear . Does anyone have a source for larger or clearer copies of the schematic?
It’s a RCA Globetrotter c8-16January 12, 2020 at 7:43 pm #12819
Here are the schematics from my red book. I hope they will work for you .
You will notice that they cover other models as well. If they are not readable
let me know and we can see if there is a way [through this forum] that I can email them to you.
So far I have not found a way to PM you or email you. [and I have looked everywhere I can think of]
I used a 6E5 in my radio and I have found that If I follow the schematics, putting in what it calls for, the radios work fine.
Although if you have a book on tube substitutions you can always use the substitute tube that the book says will work.
Dan in Calgary
PUT YOUR CURSOR OVER THE PHOTO AND A RED DOT WILL APPEAR. CLICK ON IT
- This reply was modified 2 years, 7 months ago by Dan Walker.
Attachments:January 14, 2020 at 7:16 pm #12826
Thanks guys! John, I have the booklet that came with the tube tester.and on the inside cover it says “SYMBOLS USED IN THE NOTES COLUMN” Then lists “E- use clip with Black wire” and so on,
but the notes column is blank for those 4 tubes . I will cautiously try the Black wire clip and test them again. As far as the other 2 tubes not in my listings, I’ll get them tested where I buy my tubes. The guy has 3 or 4 tube testers and tests each tube you buy in front of you before you leave.
Dan, Thanks for that! same one I have, but a much better copy. I can now read the values on the caps!. Looking closer at the radio, I am concerned that I will have issues identifying the resistors. The only other radios that I got going (2) were American 5’s and you could read the resistor stripes and decode them. This thing has dots and so on, no color code I can make out in sight. I’m having serious reservations forging ahead until I get a lot better at this. I’ve done a lot of reading and get the fundamentals, But I think I’m going to put this one on the back burner. MY Philco Hippo is kinda hummy and fades away slowly when playing, so I may have a look at that one first.January 15, 2020 at 10:23 am #12828John GreenlandCVRS Member
When it comes to the two flying leads, the manual says to always use the red lead unless stated otherwise.
I found that note on page 8 of the manual that is on line.
Good luck.January 15, 2020 at 2:51 pm #12829
Thanks John! I will try the Red lead. After some reading that I should have done before buying it, it seems this tester is better suited for T.V. tubes and tubes more from the fifties. My bad, jumped the gun.
January 16, 2020 at 7:53 am #12831
- This reply was modified 2 years, 7 months ago by garykuster.
I don’t want to step out of line here , but I usually don’t do anything with the resistors unless the radio does not work after recapping.
I have found that these old radios have a tolerance of about 20% with respect to the resistors, and if anything they usually go up in value.
Sometimes it is not real easy , but you have to follow the schematics to find the value of a resistor
If you have changed all the caps,checked out the transformer,cleaned the volume and tone controls,cleaned the band switch,tested the tubes
then that is a good start.
I usually have a good look at the resistors and see if there is any indication of overheating [dark brown areas,or bubbled sides].
Keep plugging away,and take your time and it will come together.
Dan in CalgaryJanuary 16, 2020 at 8:02 am #12832
Just a note here GARY:
You mentioned the the resistors have dots.
The way the read these resistors is the B__E__D method.
That means start with the body color B
Next is the color of the end of the resistor E
Then the dot color D
You can look up a chart for decoding resistors on the internet
Dan in CalgaryJanuary 19, 2020 at 5:09 pm #12853
Thanks Dan, Sorry for the slow response as these messages are no longer forwarded automatically to my email even though I ticked the box. I have blown up your copy of the schematics and am finding the caps 1 by 1 and matching them to the replacement parts list. I have ordered caps before for the tube tester and I may have a question or two about what type of caps are best, but I will have a look for them first and see if I can figure it out.
Thanks everyone for the advice so far, GaryJanuary 19, 2020 at 7:32 pm #12854
Dan, et al,
O.K. I went ahead and ordered the pre WW2 radio axial cap kit which covers all the Mfd caps except for the 3 higher value ones that i ordered separately. I could not find a suitable “kit’ that contained enough of the MMFD Caps that I needed so I ordered those individually. However, 5 of them I was unable to easily find so I ordered the closest values I could get.
Is this O.K.? or should I look harder on line for the correct values. For example: I need a 115 mmfd and could only find a 110, also i couldn’t find a 175 mmfd and went with a 180 etc. I spent zero time looking so far except at Justradios.
January 27, 2020 at 12:28 pm #12893
- This reply was modified 2 years, 6 months ago by garykuster. Reason: correction/addition
Good progress today!
First, thanks John for the intel about the leads. Using the Red wire, all the tubes tested good with the exception of the 6F6 which tests weak. I have replaces several lengths of wires as some were bare with insulation flaking off. Next replaced the line cord, hit it with compressed air and cleaned out years of schmutz. I have replaced about a third of the caps (the easiest to reach and read) and the radio now works and receives Am and short wavy noise on the other 2 settings. The volume control works great after a deoxit bath and the tone control works as well. The audio is understandable, but really muddy and unclear sounding.
Could be more caps or the 6f6 which is the output tube. Speaker sounds ok considering how many tears were repaired in the past. There are also 2 caps installed during a repair in the late 50’s and they make no sense to me yet as the values don’t show up in the schematic. So far I’m pretty pleased that it is already sorta working. Thanks for everyone’s help!!
Gary in Montreal
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