**Mea culpa. I was thinking BWD 521. **The 521 had no internal cratcule, but was, of course, a PDA tube. **The 521 is a 30MHz device.
**I stopped using my BWD when I bought my first Tektronix. The BWD was nice, because it can be serviced economically.
I've got a 521 with the dual beam CRT. The poor old thing's got drifting components right through it and the rotary switches keep developing tin whiskers. CRT has always had internal leakage between the guns, so changing the brightness on one affects the other (yes, I've measured the leakage right at the CRT's pins).
If anyone wants this CRO with differential vertical amps, I think I'd give it away...
Bob
Location ?
Southern Sydney
I keep hearing rumours that Australia Post staff have a lot of fun with packages marked "Fragile". That's what I was referring to.
I've done a web page complete with all relevant communications between Aust Post, the Ombudsperson and me. If you liked Sir Humphry's beaurocratic red tape in "Yes Minister", you might find it interesting...
Bob
I sent an artical today marked FRAGILE in huge letters with this way up do not throw etc , and a logger.. will be interesting to see what happens . Qld to Vic
I reckon the mail handlers will have some fun with that! Please tell us what the logger recorded.
I have a 50Mhz module for mine.
If you are offering the 521 Parts and Tube I will not turn them down ..... ;-)
Regards Richard Freeman
After I removed the external rubber sleeve, some of the aquadagged glass fell into the tube and now I can see that at least one of the gun support "rails" was snapped by the shock. The deflection plates are rattling around, shorting to each other and possibly the aquadag, and it's lucky it didn't take out some of the circuitry when I powered it up. I've added a close-up photo to
DSE actually sold me a replacement at a very reasonable price. The first bit of good news in all of this.
The only problem with the new tube is that the intensity pot needs to be about 90% of full clockwise before I see the trace and it's not real bright at full clockwise. Is your Q1803 like that? I got the schematics for it, and there's no sub-intensity trimpot, only a trimpot for setting the G2 voltage which I presume's the astig adjustment?
Cheers Bob
"Bob Parker"
After I removed the external rubber sleeve, some of the aquadagged glass fell into the tube and now I can see that at least one of the gun support "rails" was snapped by the shock. The deflection plates are rattling around, shorting to each other and possibly the aquadag, and it's lucky it didn't take out some of the circuitry when I powered it up. I've added a close-up photo to
** Would they sell me a spare for the same ??
Looks like those tubes are tad fragile ;-)
** No - the trace is visible from the 8 o'clock setting onwards.About 1 or 2 o'clock is my normal setting in subdued room light = about
50 to 10 lux incident on the screen. ** Yep........ Phil
You're not wrong. Whatever happened, the forward part of the gun assembly's a real mess now.
I don't see why not. By 'very reasonable' I mean a bit over $50. Cheaper than a new CRO, anyway.
The glass is fairly thin, except on the flat face of course.
That's what I'd expect. Looks like I might need to adjust the value of the intensity limiting resistor in series with the intensity pot/rheostat. Unless this little incident's damaged something else...
Thanks for the info. It always helps to compare a repaired one against one which has been OK from the start. :-)
Bob
I've just torn the CRO apart and checked everything related to the G1 voltage adjustment. My schematic shows R115 as 33K but the actual resistor's 75K. Seems likely that they select them on test. Now if only my component collection was still here, not where I'm working...
Bob
"Bob Parker"
** You bet.Dem tubes are exactly as " dim as they sim " .....
....... Phil
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