New to Forum- 47-1230 is my 1st Restoration - Printable Version
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RE: New to Forum- 47-1230 is my 1st Restoration - morzh - 08-30-2018
Oh.....I hope you have the speaker connected when doing all these DC measurements.
RE: New to Forum- 47-1230 is my 1st Restoration - Greggshere - 08-31-2018
Yes I have had the speaker plugged in Terry, thanks for asking. Last night before going to bed I tested every pin on every tube per the Samsphoto fact sheet, about 70 in all. I wrote them all down and will post the ones that are way off when I get home later. I think I have a few spread tube sockets though because several seemed pretty loose and when I would touch them with my probe I would either get hum or static.
I plan to investigate each circuit that appears to be way off to see if I wired something incorrectly. After soldering about 300 connections it’s certainly possible I did something else stupid. No I did not get any stations when I hooked up the loop antenna. Thanks for your help and patience with me.i did notice one of the square cans on top is missing an adjustment screw. I’ll post a picture of that later. Also I noted that I will need to get a signal generator in order to set Thisbe up? Anything I need to know before I buy?
RE: New to Forum- 47-1230 is my 1st Restoration - Radioroslyn - 08-31-2018
>Yes I have had the speaker plugged in Terry, thanks for asking.
Actually that was Mike that asked. If the spkr wasn't plugged in you wouldn't have any hv at the 6V6's. Never try to operate the set w/the spkr unplugged you can easily damage the power supply by doing so.
> After soldering about 300 connections
My you've been a busy little bee!!![Image: http://philcoradio.com/phorum/images/smilies/icon_lol.gif]
>Thanks for your help and patience with me.
My pleasure. Gotta start somewhere. Although this set is a bit more difficult that the average bear.
>I did notice one of the square cans on top is missing an adjustment screw.
Maybe maybe not. Not sure if all of the cans have two or four adjustments.
>Also I noted that I will need to get a signal generator in order to set Thisbe up?
Yup. It's a good tool for troubleshooting aid too.
>Anything I need to know before I buy?
Of course!!
RE: New to Forum- 47-1230 is my 1st Restoration - Greggshere - 08-31-2018
Thank you Terry, I was out all day and just finally got back downstairs to the workshop. Attached are the voltage readings I got on all the tubes, along with the sheet showing what they are supposed to be. I haven't yet looked into anything yet, but thought you might see something with your experience. Also I attached a photo as it sits currently in case you see something I did obviously wrong, just from an electrical standpoint. There's also a picture of the one can that seems to be missing an adjustment screw.
RE: New to Forum- 47-1230 is my 1st Restoration - Greggshere - 09-01-2018
I went down and made a quick comparison and rechecked a couple to make sure I had not screwed up. I mean it was like 12:30am when I took these last night. Anyway, the ones I highlighted in heavy pink are way off, and the ones with just a pink line are a little off. Disregard the 6V6 tube pin 2 readings from last night. I rechecked them and they were correct at 6 volts AC. I had the meter on DC apparently. Anyway it doesn't seem quite as daunting as it did, since most of the voltages are pretty close. I need to did into the ones in dark pink to figure out what I might have done incorrectly. Updated sheet below.
RE: New to Forum- 47-1230 is my 1st Restoration - Greggshere - 09-01-2018
Also I found a low frequency signal generator on Ebay with the below specifications. Does this look like what I need to do this sort of work?
Specification:
Frequency range: 10Hz-1MHz, 5 files
Accuracy: full scale ± 5%
Output impedance: 600Ω
50: negative 50 dB, and can fine tune
Sine Wave Output:
Output voltage: 5-6V RMS
Distortion rate: 500Hz-50KHz is not greater than 0.05%, 50Hz-500KHz not greater than 0.5%
Output smoothness: 1KHz reference ± 1.5dB
Square Wave Output:
Range: 10Hz-1MHz
Output level: 10V peak value
Rise time: 0.5 microseconds
Synchronization Performance:
Range: 1V voltage per input can change the oscillation frequency 1%
Input impedance: 10KΩ
RE: New to Forum- 47-1230 is my 1st Restoration - Greggshere - 09-01-2018
So I did some resistance checks on the affected tube pins and circuits and found an open 68 ohm resistor on 6BA6 pin 7. I changed that resistor and corrected that. On 7F8 I found pins 3 & 6 open resistance. Tonight I highlighted my schematic for those circuits and the components I need to check tomorrow. I also found I have 6AB6 Pin 6 wired to C102A and I believe it should be C102B. C102A has the R100 resistor in that circuit whereas C102B does not, and according to the schematic Pin 6 does not connect to the R100 resistor. I plan to change that tomorrow as well, and I'm hoping that since the relationship of my off voltages and resistances seem to affect the 7F8, 6BA6, & 7R7 circuits and they have several components in common, when I find the culprit or culprits, all of my voltages and resistances will come into line.
RE: New to Forum- 47-1230 is my 1st Restoration - Greggshere - 09-02-2018
Man I have been racking my brain trying to get these voltages and resistances in line. I found one bad resistor and a couple I used an incorrect one. I also found I used an incorrect cap mf on one location and also was missing a resistor. Long story short, I guess after changing so many components my brain started farting. Anyway, the good news is I am making progress. I got the two 6V6 pin 2 voltages corrected and the 6BA6 pins 6 & 7 voltages corrected. The only ones I am having a time with is the 7F8 and the 7R7 and after checking everything I am at a loss.
I made a little bit of progress on 7F8 pin 3 I got it from 289V.DC to 228V.DC and on pin 6 it went from 240V.DC to 222V.DC. they should be 103V.Dc & 165V.DC respectively. Also both test open in resistance to ground and I see no reason for it. They should both be 190K. Pin 1 is still 0 and not -6.6 and pin 8 is 0 instead of -1.5.
On 7R7 pin 4 has 33V.DC and should be 3V.DC. Pin 5 is 220V.DC and is supposed to be 92V.DC. It also tests open on resistance to ground. Pin 7 is 45V.DC and should be 1.1V.DC. Other than that all other voltages are within tolerance.
Any ideas or help would be greatly appreciated.
RE: New to Forum- 47-1230 is my 1st Restoration - Greggshere - 09-03-2018
Any ideas? Thoughts on whether or not the 7F8 tube might be bad?