Thanks for your encouragement! BTW: I used LTspice, which is free and comes with a nice library of standard parts (and of course the entire catalog of Linear Technology parts...;-). Here is the link: http://www.linear.com/designtools/software/. I think it is possible to add other manufacturers parts to the library as well. Rudy

Hi Martin, Intrigued by your comments I decided to learn to do a circuit simulation in Pspice. I was able to get the volume lamp circuit running on the computer (see screen shot below; scroll to the right to see the voltage/current traces measured at various points in the circuit). You are absolutely right that the transistor type has not much influence

Seems your 4002 board looks exactly like my 4004 board that I just fixed. From what I learned about my board, I would say that your two TIP transistors are likely o.k, if your 33 light comes on after pressing "33" and the motors spins (the TIP next to the power entry point turns on the rest of the circuit when the 33 button is pressed), and

Thanks for the insight!! I always wondered what the letters in those transistor types meant etc... I realized I need to hit wikipedia a bit and ramp my transistor knowledge!...;-). Rudy

It did have "modern" lamps installed (although with a fairly high 26R resistance). I wish I had had a BC558 on hand yesterday to try what happens when exchanging the 557 with it...It did occur to me too that the exchanged BC549 transistor may have had a problem, but it shows nice rectifying I/V curves with a ~700 mV turn on... Rudy

I thought this may be an interesting little detail of interest to the community: I noticed recently that the volume lights of my BM1900 were acting unevenly, i.e. the volume "down" light was always brighter than the "up" light, i.e. not even at full volume was equal brightness achieved. I assumed the correct way would be that at

And here the conclusion: It turned out that 2TR22 (the transistor sensing the "stand-by" button) had a burnt through B-E junction. This apparently resulted in a permanent stand-by request, competing with turn-on requests from the other buttons.

Hi Vintage Community: After a recent re-capping and re-lamping my BM 1900 worked very happily for some time. Now, out of a sudden, it started the following strange behavior: When touching one of the program buttons to wake it up from stand-by, all that happens is that the relay starts clicking in ~150ms intervals and the lights briefly light up in sync

Playing with my now working 4004, I started wondering how the arm is supposed to lift exactly when pressing "stop" or "<" / ">". Right now, when pressing one of these buttons, it seems the arm starts lifting at the same time as the lateral movement begins. This results in a ~45 degree "take off" angle of

Final conclusion: Once I put in a different cartridge (the dented one is dead) it played a record very nicely. Tracking seems o.k. (at least as far as I can tell...this is my first 4004...). However, I realized the output relay did not work. After contact spraying and a very slight sanding of the contacts this was remedied, too, and it seems full functionality