[For fun - What is your degree?]

I am currently working towards a BA  in IT/Media Studies, University of Wales, Lampeter.

[Stepper motor driver]

Good point, the voltage isn't marked on it, I assumed it was a 12V motor.  I'll try it on 5V and see if it's better

[Stepper motor driver]

Success!  Circuit working well, even though it's still on my breadboard.  The stepper motor becomes hot, more than 35C, is this normal?  Total circuit current is 225mA at 12.25V.

[Camera/monitor adaptor]

Is it possible, using an adaptor, to connect the composite video signal from a camera to a VGA monitor?

[External aerial for FM receiver]

As most commercial FM radio receivers are not fitted with an external aerial connection, does anyone know how to add one, for use in poor signal locations such as caravans.

[AWG (American Wire Gauge)]

According to a table in an old book on Wireless Coils, Chokes, and Transformers, from the 1930s, 24AWG is 0.020", 0.508mm diameter. Safe current is about 1.5 amps (at 4000amps per square inch).

PS. I like the Desktop!

[Stepper motor driver]

Thank you, I'll add the capacitors, remove the relay, and see how it goes.

[Stepper motor driver]

Here is the circuit I am using


The relay is so as to produce a full 12volt pulse, not available from a 555 directly, though contact bounce could be possible.  The published circuit uses TIP31's or even 2N3055's but the BFY51 should be suitable for the motor.  The project is to operate a camera shutter, with a cam and follower, for time-lapse photography.

I also built a circuit using a LM324 and a SAA1027, but it is erratic, going into reverse at times.

[Stepper motor driver]

I am trying to build  a simple circuit to operate a stepper motor at 48 steps per minute.  I am using a 555 to generate clock pulses at 1.25Hz followed by a 4070 and a 4027 to sequence the motor via 4 BFY51s.  But, the clock pulses are too low a level, so I have inserted a sub-min relay to supply a 12volt pulse to step the 4027.  But it doesn't, should it?

[free schematics links, great page]

I have a workshop manual and schematic for the Truvox '90' series tape decks and portable recorders, from the mid 60's; can copy.

Looking for circuit of Sony STR-333L and TC-U30 from 1978.

[SE Labs oscilloscope EM102 schematic]

I have this oscilloscope, dated 1965.  It works, sort of.  A schematic would be a big help for refurbishment purposes.

[How many people here scrap old electronics?]

I remove only the parts I can test.  When I was at school, a friend and I salvaged resistors and capacitors, but we found that Rs were usually gone high, and the Cs were leaky.

Now I keep only the boards, and I do sometimes find parts I use, plus motors, relays etc.  The multicoloured wiring comes in handy.

[Switch-mode Nicad charger failure]

The 24volt battery discharger/charger for my Yamaha electric bike has stopped working.  No repair facility, but a new one costs