Little Maestro T105.

[tiv48]

true chris but the multivibrator has harmonics up to rf and this also works as a tracer
rob t

[OldTickTock]

Agreed Rob and I would build your device in preference to my dirty method, it's an option if Joe feels lazy and or has not got all the components to hand.

I use my trusty Taylor Model 22A, you can find where the signals are

[Joe]

Thanks for that, Rob, it looks within my capabilities and I've got most, at least, of the bits in stock.

I was going to use my 555 based continuity tester but don't want to get the HT up that or anything else so the question really was: where to connect it, or where not to. Thanks for the caps tip.

If this proves to be my final post you'll know I've guessed wrong. "Wish me luck as you wave me good-bye. Cheerio, here I go on my way..."

[Joe]

I'm still alive, which is more than I can say for my continuity tester. The first thing I poked was the volume control and damned near deafened myself so the AF amp is definitely working.

Add an NE555 to Saturday's shopping list. Glad I didn't use my MP3 player!

[OldTickTock]

odd! I used to use the mp3 player a lot until I got my test kit sorted, I always started at the volume control too and worked backwards. The mp3 player still lived to tell the tale and still works I just dug it out of the forget me box.

[Joe]

It's even odder than that. I've got two of those testers so I tried the good 555 in the damaged one to make sure that it was that that had blown. It then worked OK and, most oddly, the 'Damaged' one works in the other tester but not the one I'd used as a sig gen. There must be something very odd in the electronic lay-lines 'round here.

I've tried connecting an expendable trannie through the Pilot and that survived and sounded surprisingly good.

I'll investigate more later and am hoping it isn't one of the coils that's gone as the resistors I'd replaced were so wide of their correct values that they may have had stupid voltages applied to them.

It was also interesting to see the brilliance of the dial lamp vary as it warmed up and how it also had that 'Half-wave Flicker'.

I think I'll be going for AC/DC sets in future as they seem a sight more co-operative.

Thanks for the advice.
Joe

[tiv48]

heres a link that may be helpful it shows for a solid state radio but the ideas the same for valves http://my.integritynet.com.au/purdic/squ...erator.htm
rob t

[Joe]

I've had a more systematic go with my continuity tester/signal generator, this time starting at the other end.

I get a bleep out of the speaker no matter what I touch, ie every contact on the ferrite rod, wave-band switch, tuning capacitor and pin 2 of the valves. I did spot one bad joint - an original, not one of mine - so will have a closer look tomorrow as it'll be easier in day-light.

I played the tranny through it a bit more and have been very pleasantly surprised by how good the sound quality is; I think I'd been prejudiced by the case and was thinking it had been cheap and nasty in its day so still would be. Doing something with that will be another challenge.

I don't know if it means anything but it consumes a current of 170mA. While playing about I discovered that the 250VAC range on my AVO is u/s so that'll be another interesting job. Oh well, it keeps me out of mischief.

- Joe

[OldTickTock]

When you get around to your AVO, this servicing manual will be of great use http://www.bygonebytes.co.uk/Meters/Avo%...mation.pdf
Chris

[Joe]

Thanks very much; I'd been looking for something like that.

Cheers
Joe