Grunow 1191

[TC Chris]

I'm not at home this weekend but there I have some of those reprints, Most Commonly Requested Diagrams"or some such, think they were Beitman's. I can check this next week when I'm home if you don't get the info from others.

A work around would be to bypass the old socket with an extra tube socket, using a resistor that you think is right, if you have an extra non-octal socket with the right pin pattern.

Chris Campbell

[electra225]

Thanks, Chris, that will be a big help.

[electra225]

Replacing the resistor in an eye tube socket is a miserable job. Plus, I don't see a difference in performance. I still have a lazy eye tube. I have aligned this chassis twice in the past two days. I THINK I have it where I'm not making any improvement in performance. I may run it for a time on the bench, then align it again. It sure was messed up as far as the alignment is concerned. I can't imagine that what relatively little I had done to it actually fixed it. This radio chassis has been "fixed" then found to be "broken" more times than I care to count. The sensitivity is pretty good, volume and tone fairly good. I'm not sure this will ever compete with my old Stromberg-Carlson or the Philcos I have, but it is better than it ever has been since I've owned it. I want to swap a couple of tubes that I have, but have to dig for to see if they make a difference. There is some noise I can't account for and there seems to be more background noise and hiss than there should be. I need to order a dial drive belt and fix the spring on the tensioner before I put the chassis back into the cabinet. I can't imagine my step-dad or the family radio repairman not aligning this chassis if that was all that was wrong with it. My step-dad was an electronic genius, and I can't imagine him saying this radio wasn't worth fixing just because it is a pain to align.

[TC Chris]

Have you put a voltmeter on the eye tube to see what kind of grid swing you're getting? I don't recall ever looking at an eye tube in the tube manual so I have no idea what kind of voltage is required to close it. My tube manual is enough steps away that I ain't gonna go look. I just cooked my bike chain in melted paraffin wax and need to go out and put it back on the bike first. We're supposed to get rain tomorrow so it might be a driving day but you never know. Riding the bike is one of the things I do to keep the first foot out of the grave. Or maybe it's the second foot.

Chris Campbell

[TC Chris]

Get the bike chain on--the whole process after rigging up a portable light outside the garage door in the dark--the actual chain installation-- took about 2 min. Last time it was an extended #@$*&!!!!. So I came in and grabbed my 1961 RCA manual. They show data for the 6E5, and that one requires -6.4 to -8.0 volts to close the angle, depending on plate voltage. 0 volts give a 90-degree angle (open). Or maybe it's vice-versa--they talk about "shadow angle." 6U5 uses -22 and 0. I'll bet yours is a 6N5, for which my manual does not give data. But I wonder what your grid shows.

Chris Campbell

[electra225]

This eye tube is a 6U5. I'm not sure I understand what I need to be measuring. But that's a good idea. I measured plate voltage, and quit there. Maybe I'm not done yet.......

[TC Chris]

The triode grid voltage controls the eye's action, according to the tube manual. So the book suggests that the grid voltage should swing between -22 and 0 to get full action on the eye. If the voltage isn't moving much, neither will the eye.

Did you ever get the schematic? If not, remind me to look in the box in the garage tomorrow.

Chris Campbell

[hermitcrab]

Check that 1 meg resistor in the tube socket... these drift way up and stop eye tube from varying...

[electra225]

I replaced it. It measured 1.395 megohms. I'm not sure that was enough to cause a problem. That was a miserable job. You have to drill out a rivet that holds the socket together. Then, how do you put it back together? Plus, after all that nonsense, the eye tube still doesn't move much. I need to check that grid voltage and see what that gets me.

[electra225]

I still have the lazy eye tube, but the radio works just fine. I really regret the fact that we used this radio for a plant stand for 40 years simply because nobody cared enough to figure out what was really wrong with it. Cousin Calvin told grandma this radio had been struck by lightning and wasn't worth fixing. Grandma liked this radio and kept it in the back bedroom, unused, because grandpa had given it to her for Christmas. She couldn't bear to part with it. Cousin Calvin, the RCA dealer and TV/radio repairman, just didn't want to fool with it. I can't put my finger on the ONE thing that helped it to work like it should. It needed a little bit of everything, if you have followed along with this topic. I'm using two test leads for an antenna, so it doesn't need much antenna to get local stations. I'm sure if I was to do some DX-ing it would need more antenna. I don't believe it will outperform the Stromberg-Carlson 1121 I have due to the fact the front end isn't as robust. I have been running it for two or three weeks, listening to Western Red. It still needs a dial drive belt, which I feel better about ordering now that the radio works.

[TC Chris]

Did you ever post a photo?

Chris Campbell

[TC Chris]

I found a model 1181 schematic online--tuned RF amp, two IF amps, and a discriminator for detection; P-P 6L6 outputs. Is your 1191 similar?

Chris Campbell

[electra225]

The 1191 is almost identical to the 1181 with the exception of the output tubes. It had P-P 6F6, now has 6V6. It has tuned RF, two IF stages. It has five audio tubes, plus the 6H6GT detector. Grunow made this model with an "expanded" tube count, if you get my drift. This model uses separate detector and first audio tubes. I tried using o-rings for a dial drive belt, but they don't last long. You have to disassemble the dial mechanism to get a belt on. The dial has to be timed to the tuner, not something one would want to do frequently.

[TC Chris]

I have read about people using superglues (cyanoacrylate) to end-glue belts together. It yours has some way of releasing tension so you could manipulate the ends together and then re-tighten after gluing, it might be worth a try. I haven't tried it yet but it sounds like a good way to deal with those situations where the work required to make simple fix leads to deferring the work indefinitely.

Chris Campbell