I need a signal generator for use in my hobby shop and looking around and trying a few things I have come to realise the BWD Minilab (McVan) 604 would perfectly satisfy my needs (I need something to generate both 455KHz and 10.7Mhz to allow for radio IF alignment).
So I tried to find one of these units s/h but no luck.
Looking around some more I found the factory manual and it seems it's not that difficult a build so I decided to try and build one (at least the signal generator, amplifier plus counter and display section). The manual I found comes from here:
https://www.kevinchant.com/uploads/7/1/0/8/7108231/minilab_604_v2_maintenance_manual.pdfThank you very much to the gentleman who put it up for the rest of us.
Now, the manual is quite comprehensive but it does leave some questions unanswered (at least for my level of understanding - I am not a qualified electronics engineer).
The questions the manual has left are about connecting all the separate circuits in the signal generator section (if you check the relevant schematic you will find a few separate schematics, some are clear where they should connect, some not so much).
If you have a unit and could help with some info or pictures, it would be very much appreciated, thank you.
If you are an electronics engineer and could guide me, it would be very much appreciated, thank you.
See picture attached for schematic:
Another set of questions relates to finding modern equivalents for the chips/semiconductors used in the original design. Most of these are obsolete. You can still find them, but they are most likely cheap clones and I am not sure how well they will perform so I would prefer to use modern equivalents from reputable manufacturers/suppliers.
I should add, I ma looking for direct replacements so I do not have to modify the schematic (because I wouldn't know how).
So here they are:
LF441 - I found LF444 - can I use that?
LM353 - is TL072 a direct replacement?
LF351 - ?
MC1445 - ?
LM6361 - ?