Motorised Cinemeccanica rewinder

[Mike Sharples]

Hello

We have a motorised Cinemeccanica rewinder. We need to replace R5 on the board pictured which believe is a 2.2K ohm wirewound cement type. Struggling to find one in available in the UK. Wondering if anyone knows where i can get one or an alternative solution, whether it can be modded to take the metal finned type. The original split and is currently held together with a bit of wire, runs as bit hot at higher speeds.

Any help appreciated.

Also while i'm on, we're in the market for a pair of zenith 6500 lamphouses if anyone knows of anywhere willing to part with some. The Vic 8's are currently sporting a pair of 4000's with 2.5k lamps in but we need to move to an alternative due to lamp supply issues and i've been told Horizontal 2k lamps would be the way to go and we are looking for something that looks right.

Mike

[Tomek Lecocq]

Did you look at the usual electronics components retailers? (RS, Farnell, Mouser, Digikey, ...)

[Alan Lyman]

according to my schematic,R4 is 2k2 15w,and R5 is 50ohm 5w.R5 is for braking the motor.R4 is to ensure load on the thyristor. any resistor with same values can be used

alan

[Mike Sharples]

according to my schematic,R4 is 2k2 15w,and R5 is 50ohm 5w.R5 is for braking the motor.R4 is to ensure load on the thyristor. any resistor with same values can be used

alan

Hmm i'll double check the board make sure i haven't misread the numbers but useful information regardless, it's definitely one or the other, thanks.

[Mike Sharples]

Did you look at the usual electronics components retailers? (RS, Farnell, Mouser, Digikey, ...)

RS and Farnell, yes. I'll check the other two, thanks.

[Randy Stankey]

While you're working on it, you'll probably want to take a closer look at the board. The screw in the bottom, right corner shows some corrosion from heat and moisture. The circuit board, itself shows a bit of heat stress and it looks like there has been work done on the board, before. You'll want to, at least, give it a good cleaning.

Many of the solder joints show some corrosion from heat and humidity. They're just crusty from age, I suppose. I also see a few solder joints that weren't done properly. It looks like five or six of them but it's hard to tell from the picture. If they are, indeed, bad solder joints a board like that shouldn't have made it off the QA inspector's desk.

Maybe somebody should check those joints and fix them if they need it then, maybe, reflow the rest if they need it.

[Mark Gulbrandsen]

I'd mount that 15 watt resistor off the board and on to the metal enclosure the board mounts in. There are resistors one can buy that mount this way, and include mounting legs. That board is pretty small and as Randy said shows signs of heat damage. They are still in business in Milan, so if you don't have an electronic parts vendor, you can writeto them. They may have spare boards as well.

[Stefan Scholz]

Any resistor in the same range and load, I'd go for those in an aluminum housing, mount it to the metal enclosure. These are pretty common to find at most electronics vendors, they have already been named. You can also use a classic 10 W light bulb. It's ensuring a basic resitive load on the thyristor control.