Hello from Cuba

[Terry]

I don't know if there is any logic to testing emitter/collector voltage but I was curious and not sure if it tells me much.

There sure is! It can tell you a lot!

Might I respectfully suggest that you go back and read the comments from Lawrence and me on the subject in posts 79 and 80 in this thread ...?

As for your 5 volt/7 volt puzzle, you are comparing apples with oranges here. Assuming that the voltages are correct, then that is how they were designed to be.

Also, what were the respective battery voltages? You are not going to find a 7 volt supply in a 6 volt radio!

I have a 1.6 litre engine and automatic transmission in my current car. It's predecessor had a 1.8 litre engine and manual transmission. The both get/got me from A to B. Both their engines work in exactly the same way as a neighbours 2 litre car and another with a 1.3 litre engine across the road. Do these differences puzzle you?

[Nowhere-Man]

It is true voltages may differ as I have a spec anode voltage that is meant to be only about 64 volts. However, to answer your question 9 volts was the source voltage for both transistor radios. At the time I thought 5 odd volts was a bit low but, for now, it is just filed to the back of my mind.
Miguel has found breaks in the holders (the legs) so will keep checking.
Now you mentioned engines, I do that as well. My current engine has a cable operated stop solenoid and hydraulic gearbox. It uses epicyclic gearing. It was made around 1974 but still running. I found out the gearbox is pretty similar to the Sturmy Archer cycle mechs used prior to the modern derailleur. I also worked on vintage VW engines like the Jetta (also Seventies).
I find the old engines more robust.

[Nowhere-Man]

Tonight I was initially analysing the circuit to my East German radio project but winded up doing radio wave calculations instead. What set that off was the KW and UKW oscillator windings.
Getting back to the main thread of Cuba, I thought I could point out Nikita Krushchev's son Sergey has a Phd in electronics. He was involved with the Soviet space program and, impressively, Sergey has other Phd's too. He's a pretty decent political historian. The odd thing is the President Krushchev himself was not so popular in the USSR due to his appearing kind of unsophisticated and not well educated. Yet, the fact his son has more than one Phd is food for thought.
I was talking with a Russian friend who told me her friends had visited Cuba and, sure, lots of technical equipment from the USSR is to be found there. It wouldn't surprise me to encounter those TURIST telescopes that came in a black flask with a strap.

[Terry]

That reminds me of a Soviet Foreign Minister - Andrei Gromyko, I think - who played the 'No speak the English' card to his advantage.

In fact, his command of English was excellent so that he understood everything perfectly but while his interpreter was translating what was said into Russian, he used this for additional thinking time before he had to reply!

[Nowhere-Man]

That scene was depicted in the film on the Cuban crisis. The features also has some analysis from Sergey Krushchev.
Today I (and many others) are experiencing blocked or downtime access to Russia Today. Can't get it on my mobile internet. People are saying try the Spanish link and that did work.

[Nowhere-Man]

Good way to test transistor legs in the holders. Wrap one end of meter probe with telephone wire. Stick other end of wire in socket. Test other side of board. So far all is well except for one tiny hole in a solder joint. May be the humidity in Cuba has caused brittle legs to be common.
So far the legs appear to be OK. I am doing a crash course on Soviet P and MP transistors. Need to buy a scope soon.
I noticed Chas Miller wrote a book on transistor radio repair and it's about 20 quid second hand on Amazon.
PS I discovered a faulty AF117 on another radio. However I find these to be generally a very hardy transistor.

[Terry]

 I discovered a faulty AF117 on another radio. However I find these to be generally a very hardy transistor.

In which case you have been very lucky! All AF11x and OC17x transistors are plagued by a tin whisker problem which has been discussed at length on various forums - it was even the subject of a very interesting NASA investigation but, unfortunately, the NASA site http://nepp.nasa.gov/whisker/anecdote/af.../index.htm comes up with a DNS error. Perhaps it's been TRUMPled on ...?

However, our very own Mark Hennessy has written a detailed article on the subject but without the fantastic electron microscope pictures in the NASA report.

[Nowhere-Man]

Put it this way: I have a very early 1960's Philips car radio crammed with AF117's. It works just fine.
However, the other night I read an article online about transistor radio repair (as well as Mark's tips and essay). Well, this guy had his RF stage neatly summarised. It was check the audio stages first and if that's all OK, it will be the AF117's. Remove, test and zap. Put it back in circuit and your radio will be restored. Maybe that is the case. Still what I like about the AF117 is at least you can fix it. I love the sleeved leads as well.

[Nowhere-Man]

Just to be sure, I rechecked the AF117's. One of them is faulty. The others seem OK. I looked up the pin configuration and over the days I swatted up on my "holes" and electrons theory.
I never really intended before to "stray" from valves as I had enough on my "plate"with those as it was.
My Soviet Tranny has a lot of MP41 transistors that seem to be used in audio stages. Never heard of them till recently.

[Old Sparky]

Regarding AF117s, I consider them to be 'change on sight' devices. 'Zapping' them may only be a temorary cure. I'm currently repairing a Perdio 'Caralux' portable in which two of the three AF117s were leaky due to the well-known 'tin whisker' problem, so I've replaced all 3 with Russian made GT322 transstors. These are inexpensive germanium transistors, available from eBay sellers, and, unlike the increasingly hard to find AF127, have lead-outs about 1" (25.4mm) long, which makes it easier to fit them in many radios,, including the 'Caralux'