07-10-2021, 12:38 PM
Hi pppenguin,
Thanks for your reply. I can confirm that I measured from the test point from the service sheet which is I think synonymous to the chassis or +ve terminal of my battery. Anyways, I decided to spend my lunch break (the joys of homeworking!) double checking my results from yesterday and of course I have made mistakes! To be extra sure I measured also from chassis and battery.
The measurements for TR4 should read:
TR4 OC71 1.2V 0.12V (1.0V) 1.3V (1.1V) 1.7V (1.5V)
As for the TR5, I took extra time to ascertain which leg is which (it's probably dead obvious to while looking at the schematic, but it's a learning experience for me
). By freeing the TR5 from the wee bracket it sits, in I realised that I mixed up Emitter and Base, so that the measurement is:
TR5 OC81D 1.5V 1.7V (1.3V) 1.7V 1.5V (1.5V) 8.8V (8.3V)
so the measurements on both of them seem to be mostly 0.2V over the service sheet, which sounds like I shouldn't worry about the transistors?
Thank you for sharing the article, very interesting. Judging by the case - serial number starting with 346, and by the fact that it has the earphone plug, it's the later Mk I (1962), colour scheme is clearly that of a C type rather than B (blue rexine and greenish plastic). I realised that I am now able to add attachments in the acceptable way, so I am attaching the front and back of the chassis together with the cabinet.
Having ruled out the transistors, what should be my next port of call? Multimeter is quite limited, should I try to build a capacitor tester with my Arduino(ish) set? Any guidance or resources will be appreciated.
Best regards,
TinaRotator
Thanks for your reply. I can confirm that I measured from the test point from the service sheet which is I think synonymous to the chassis or +ve terminal of my battery. Anyways, I decided to spend my lunch break (the joys of homeworking!) double checking my results from yesterday and of course I have made mistakes! To be extra sure I measured also from chassis and battery.
The measurements for TR4 should read:
TR4 OC71 1.2V 0.12V (1.0V) 1.3V (1.1V) 1.7V (1.5V)
As for the TR5, I took extra time to ascertain which leg is which (it's probably dead obvious to while looking at the schematic, but it's a learning experience for me
). By freeing the TR5 from the wee bracket it sits, in I realised that I mixed up Emitter and Base, so that the measurement is:TR5 OC81D 1.5V 1.7V (1.3V) 1.7V 1.5V (1.5V) 8.8V (8.3V)
so the measurements on both of them seem to be mostly 0.2V over the service sheet, which sounds like I shouldn't worry about the transistors?
Thank you for sharing the article, very interesting. Judging by the case - serial number starting with 346, and by the fact that it has the earphone plug, it's the later Mk I (1962), colour scheme is clearly that of a C type rather than B (blue rexine and greenish plastic). I realised that I am now able to add attachments in the acceptable way, so I am attaching the front and back of the chassis together with the cabinet.
Having ruled out the transistors, what should be my next port of call? Multimeter is quite limited, should I try to build a capacitor tester with my Arduino(ish) set? Any guidance or resources will be appreciated.
Best regards,
TinaRotator
