#1
|
||||
|
||||
Help with transformer schematic
Working on an airline 62-177. Someone has done some work prior to me and cut some wires so it's made it a little harder for me cause I'm not that good at reading schematics yet. The issue I'm having is that there are two extra leads coming from the power transformer that I don't think I need. The schematic shows 7 lines coming out and I have traced all 7 to the rectifier or power output but there are two extra that are taped off. Is it possible this radio used a trans that had extra leads? I've studied the attached section and the only thing I'm unsure of are the leads marked "a".
__________________
Looking for a dial glass and knobs for a R-30s Fisher console. |
#2
|
||||
|
||||
The leads marked A are supposed to connect to all of the tube's heaters (except , of course , the filaments of the #80 rectifier , which has it's own tap off of the transformer)
|
#3
|
|||
|
|||
The tubes' heaters are in parallel, BTW (not series).
Can't imagine why those leads would be taped off. |
#4
|
||||
|
||||
Got plenty of time on the bench tonight and replaced the caps. Couldn't resist plugging it in momentarily. Tubes lit and I actually tuned in a couple stations before quickly turning it back of. My eyes literally burn from tracing that schematic but I think I finally figured it out. The hardest part was locating the caps someone had already cut loose. I guess I must have done it right if it works?
BTW, there was some wax that appears to have run out of the transformer some time ago. Is it near toast? Sent from my SAMSUNG-SGH-I337 using Tapatalk
__________________
Looking for a dial glass and knobs for a R-30s Fisher console. |
#5
|
||||
|
||||
Is the transformer the original unit to the set? If it is a replacement the taped-off leads are probably center taps on the filament windings that are not needed on this set.
__________________
Sean - WØKPX |
Audiokarma |
#6
|
||||
|
||||
Transformer certainly looks vintage but it could be a replacement. I think someone replaced some caps many years ago so it's possible. Radio works, all tubes light and she plays so maybe we're good.
Sent from my SAMSUNG-SGH-I337 using Tapatalk
__________________
Looking for a dial glass and knobs for a R-30s Fisher console. |
#7
|
||||
|
||||
This is definitely a replacement transformer. My rectifier had burned out on me so I tested the voltage at the pins. 323 v at the rectifier ok? The schematic doesn't say. It lists the voltages for the other tubes. The heater voltage is correct though.
Sent from my SAMSUNG-SGH-I337 using Tapatalk
__________________
Looking for a dial glass and knobs for a R-30s Fisher console. |
#8
|
||||
|
||||
Quote:
300 VAC from the transformer to the #80 IIRC is right. Will give you 300 VDC full wave before filtering. Most old power transformers are color coded. This link will give you what you need and then some........ http://www.radioremembered.org/xfmr.htm 73 Zeno |
#9
|
||||
|
||||
That's good news, thanks. When I get a new rectifier in it I can test the other voltages.
Sent from my SAMSUNG-SGH-I337 using Tapatalk
__________________
Looking for a dial glass and knobs for a R-30s Fisher console. |
#10
|
||||
|
||||
Well, new rectifier doesn't light either. Time to lift a leg on all the old resistors and double check everything.
Sent from my SAMSUNG-SGH-I337 using Tapatalk
__________________
Looking for a dial glass and knobs for a R-30s Fisher console. |
Audiokarma |
#11
|
||||
|
||||
Quote:
1) bad tube 2) bad tube socket 3) pwr transformer, no 5VAC on yellow wires to the 80 4) somethins wired wrong. 73 Zeno |
#12
|
||||
|
||||
Ok. Hard to tell what colors these wires are any longer. There are heavy "white" ones and heavy "black" ones and some thin red ones. I've been on the road all day, I'll have to check them later.
If it is the transformer, how do I spec it and where do I get a replacement? Sent from my SAMSUNG-SGH-I337 using Tapatalk
__________________
Looking for a dial glass and knobs for a R-30s Fisher console. Last edited by Schanz; 07-06-2014 at 09:30 PM. |
Thread Tools | |
Display Modes | |
|
|