I have a problem with my 10b, the tuning drifts suddenly, and often completely out of tune. Yes, all the tubes test good on my B&K 747. (but, it might not be picking up the problem.)
Anyone have any experience in this?
I have attached a schematic.
NOTE: I was going to upload a schematic, but the size is too large. Anyone wanting one, let me know.
Anyone have any experience in this?
I have attached a schematic.
NOTE: I was going to upload a schematic, but the size is too large. Anyone wanting one, let me know.
You certainly should get rid of it! I'll give you $50 to handle shipping it to me.
However if you do want to keep it, the biggies would be dirt or corrosion on the tuning capacitor, particularly the smallest section, a cold solder joint in the local oscillator section or a bit of corrosion in the local oscillator tube socket. Possibly even unstable voltage to that section. Also look for a cracked ceramic capacitor there.
However if you do want to keep it, the biggies would be dirt or corrosion on the tuning capacitor, particularly the smallest section, a cold solder joint in the local oscillator section or a bit of corrosion in the local oscillator tube socket. Possibly even unstable voltage to that section. Also look for a cracked ceramic capacitor there.
I would 1st try to replace the local oscillator tube (V3/ 6DZ4) even if it tests good on your B&K 747.
I remember a problem to check all 6DJ8 for leakage on one of the pins, and replace all that show voltage, I will see if I can find it, when I get a chance. How is your stereo switching we used to use RatShack Photo cells to rebuild the cans.
Hi Freddy,
I'd appreciate the help.
The problem with building my own optoswitches is, in my mind, finding the *right* photocells. I'm very close to just pulling one out, and hopefully being able to read a p/n.
The way I see it, is the photocell has to be able to take the high temperatures, have the proper ohm readings, and be sensitive to the NE2's spectrum. That is one reason why I thought that perhaps the optosensor's I found for Fender amps might work.
I'd appreciate the help.
The problem with building my own optoswitches is, in my mind, finding the *right* photocells. I'm very close to just pulling one out, and hopefully being able to read a p/n.
The way I see it, is the photocell has to be able to take the high temperatures, have the proper ohm readings, and be sensitive to the NE2's spectrum. That is one reason why I thought that perhaps the optosensor's I found for Fender amps might work.
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I do not think the cells are anything you can't get. A chat with a Digitkey tech should do it. i don't think the temp is a problem, resistance range is. Look at the voltages they may have an opti device that will work. I loved that tuner, the FM is so bad I don't use one now. I use Verizon and Directv music feeds now, much better than I thought. I had tried Sirus but it was real junk. I do have a brand new Amperex O Scope for the 10b in my inventory, I would guess yours is burned pretty good by now.
Joseph Merriam
jemerriam3@verizon.net
Joseph Merriam
jemerriam3@verizon.net
Thanks you Freddy,
My scope *was* burned, but I bought a new one many years ago. (Kept the old one for, well, who knows why.) You used to be able to get the scopes on Ebay cheap, they are still easy and cheap compared to the scope tube for the Model 18.)
Yes, resistance range is the thing I'm going to be looking at.
Everyone says' how easy it is to make a new one, I couldn't agree more. However, I replaced the originals way back when I bought the 10b, (In the early 80's) with ones I got from a guy in Los Angeles. It took me hours, btw. Worked fine at first. Today, not so good.
Well, I will figure it out!
Do you remember what you paid for the tube. It didn't take you that long!!!! It took you that long for you to get your nerves under control, just to cut the old lady up. It was like doing open heart surgery on your 95 year old grandmother. That machine was a real work of art and you just didn't want to leave any finger prints on her in case she died! I replaced my 10b with a Yammy CT 7000, which sounded just a shade cleaner and pulled better on my FM4G beam antenna with a rotor. FM was not as much fun after that though. We live in a tough reception area, but the programming was wonderful. It has been great talking, good luck!
Freddy, I've heard good things about that Yammy, I know your enjoying it.
If I recall, (I've had the 10b since about 1980) I bought the scope tube about 1990, and if I remember right, paid about $50. (and believe it or not, that was twice what I paid for the 10b.) Since then, I've seen the prices on those scope tubes go all over the place.
Yeah, replacing the original optocouplers was not fun, and took me about 8 hours, since I was being *very* careful. The 10b's point-to-point wiring was done in layers,which didn't make it any easier. Shortly after, I took it in to a local tech to have him check it over, and he said I did a good job, that made me feel better.
If I recall, (I've had the 10b since about 1980) I bought the scope tube about 1990, and if I remember right, paid about $50. (and believe it or not, that was twice what I paid for the 10b.) Since then, I've seen the prices on those scope tubes go all over the place.
Yeah, replacing the original optocouplers was not fun, and took me about 8 hours, since I was being *very* careful. The 10b's point-to-point wiring was done in layers,which didn't make it any easier. Shortly after, I took it in to a local tech to have him check it over, and he said I did a good job, that made me feel better.
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I really don't use the tuner, I am in the hills 35 miles north of the city. Weak reception on the few good stations. The whole band hasn't any programming I want. I use the 40 channel music feed, or the Directv music channel feeds, and it comes over great The Verizon Classical feed is very diverse and has good dynamics. I am glad you had sucess with the opti switches. I know you are Mr. Tubie, but if you ever see a Nakamichi SR 4a for cheap pick it up... It will change your view of quality amplification... it sure did mine totally by accident. Should not cost more than $100, and less if they are broken. (easy fix) The MC and phono section is the quietest I have ever heard, It is only 60 wpc but it is a stassis amp, and it will drive any speaker with NO effort with real purity!!! Sorry, I did not see your post in my mail!!!
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