Greg Mayman wrote in a message to Roy J. Tellason:

 -=> Roy J. Tellason said to Greg Mayman
 -=> about "*BIG* TRANSISTORS" on 02-05-04  04:06.....

 RJT> I know I remember seeing some that were pretty good-sized,  in
 RJT> addition to the ones that I mentioned,  but it was quite some time ago
 RJT> and I don't recall what the size(s) were.

 GM> I think this radio must be *at_least* 40 years old. The
 GM> transistors are all the early Philips types that I first saw in
 GM> about 1954...

 RJT> Speaking of which I ran across a chip earlier today and wondered what
 RJT> it was. Turns out it's a reversing motor control chip (not steppers, 
 RJT> just a brushed motor) with braking,  apparently intended for vcr or
 RJT> audio cassette applications.

 GM> Hmmm... why would they want the braking action? Or the 
 GM> reversability? My guess is that it was for some remote or auto
 GM> control like your motorized tuning.

No,  the data sheet specifically mentioned vcr and audio cassette
applications. I can see reversibility being a good thing if you're running
a tape cassette and have a bidirectional capability in the deck -- you'd
have the mechanism switch capstans, but the motor would also need to spin
in the other direction.  VCRs? Hm,  that's a little more difficult, I'm not
that up on the mechanicals of those.

 RJT> The other cool thing about that radio that I just remembered was the
 RJT> EM84 tuning indicator tube.  Sorta like those "tuning
eye" tubes that
 RJT> used to be around (6E5, etc.) only those were octal and had the lit
 RJT> part on the end, while the EM84 was 9-pin miniature and had it on the
 RJT> side,  giving a nice little rectangular display area.  The vacuum

 GM> I remember them!

Yeah,  weren't they nifty?  :-)

 RJT> flourescent displays that I've seen in more recent stuff look pretty
 RJT> clunky by comparison. 

 GM> Darn right they do :-(

I actually have a couple of them (out VCRs) and no particular plans to do
much of anything with them.

 RJT> It wasn't on the volume control,  just another button among several. 

 GM> I knew what you meant ;-)

 RJT> Even that was fairly different from the US stuff that I was used to
 RJT> seeing,  which as you say typically had the switch mounted on the
 RJT> volume control. 

 GM> And they would often wear out the volume control carbon track
 GM> LOOOONG before anything else on the radio failed. Removing the case
 GM> of the pot and filling it with vaseline often made a very effective
 GM> and long lived cure, if the track wasn't too badly worn.

Vaseline?  First time I've heard of that being used for the purpose...

I've used all sorts of assorted spray cleaners over the years.

 GM> Silicone grease was even better when it became available.

 RJT> I'm well aware of some of the shortcomings of a mechanical pot
 RJT> compared to other ways of doing things,  and of the relative expense of
 RJT> such compared to doing things digitally -- I have a little bitty tv I
 RJT> keep here in the office and it's got a bad one in there that prevents
 RJT> turning it down! -- but I'm also beginning to *hate* pushing little
 RJT> buttons for the same function.  

 GM> Yeah, me too. I want to be able to snap the volume up or down if
 GM> necassary, not wait while it clocks along a step at a time.

Just so.

 RJT> I guess it's what they had handy.  That auto fuse was no doubt rated
 RJT> at a lower voltage,  and could've exploded quite nicely if it had
 RJT> blown.  They do put those voltage ratings on them for a reason,  not to
 RJT> mention the amperage ratings...

 GM> Yes.
 GM>  
 GM> The agents quoted about $50 to import a replacement transformer --
 GM> this was in the 70's and $50 was REAL money -- but fortunately we
 GM> were able to find one locally that was close enough in voltage and
 GM> EXACTLY the same size core size as the original!

 RJT> You got lucky,  I guess that happens sometimes.

 GM> VERY rarely in my experience. I think it was the ONLY time
 GM> everything worked out that well.

Transformers fall into the category of inductors,  a class of components
that I've seldom gotten along with over the years.  :-)

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