Hi All,
having become a very new, but happy owner of a 576 which I'm still learning to use, I have a quick ( hopefully) question on setting up the unit to match transistors.
For some boards I'm re-populating, there are two transistors specified for a position - the BC413 and ZTX384. To my eyes the information in the data sheets for both these seem comparable. However, if I put them in the 576 and select a setting that'll give me a set of curves, neither will display correctly on the others settings. As I'm initially working on the setting examples in the service manual, I have to adjust these for higher values to get the curves for the ferranti ZTX, but these will then send the BC413 off the scale. Would this be considered normal, even for alternative parts?
Many Thanks
Joe
having become a very new, but happy owner of a 576 which I'm still learning to use, I have a quick ( hopefully) question on setting up the unit to match transistors.
For some boards I'm re-populating, there are two transistors specified for a position - the BC413 and ZTX384. To my eyes the information in the data sheets for both these seem comparable. However, if I put them in the 576 and select a setting that'll give me a set of curves, neither will display correctly on the others settings. As I'm initially working on the setting examples in the service manual, I have to adjust these for higher values to get the curves for the ferranti ZTX, but these will then send the BC413 off the scale. Would this be considered normal, even for alternative parts?
Many Thanks
Joe
There is a calibration routine for the 576 in the manual. You can download at BAMA: https://bama.edebris.com/manuals/tek/576/
Treat the 576 with care and don't let the trace burn too brightly on the phosphor!
Treat the 576 with care and don't let the trace burn too brightly on the phosphor!
Many thanks for your replies, I agree, the Hfe has a big variation for both, I'm going with the ZTX's as I seem to have got these matched better as an initial sift.
The 576 is not bad, it was suffering with poor switch contact and a few other glitches which some kind owners have helped me with. Its main issue was the resistance / Voltage control which had stopped working due to some grub screws slipping on the inner shaft, that was fun to do without stripping the whole machine. I've gone through most of the calibration, just a few points left for which I need to source some close spec resistors. I'll be going though it all again once this is done. It could do with a new step switch as mine is a bit flaky. When I've got this all done I can properly start matching.
Has anyone got any pointers for setting up the 576 to get good curve displays which mimic the operating conditions the transistors will have in circuit? the ZTX will be connected through their bases, so I think theres something on it to ( compensate) allow for that? I've used the setting in the manual but it doesnt cover testing power transistors as far as I can see? I know about the pulse feature so the DUT isn't subject to heating.
Many thanks
Joe
The 576 is not bad, it was suffering with poor switch contact and a few other glitches which some kind owners have helped me with. Its main issue was the resistance / Voltage control which had stopped working due to some grub screws slipping on the inner shaft, that was fun to do without stripping the whole machine. I've gone through most of the calibration, just a few points left for which I need to source some close spec resistors. I'll be going though it all again once this is done. It could do with a new step switch as mine is a bit flaky. When I've got this all done I can properly start matching.
Has anyone got any pointers for setting up the 576 to get good curve displays which mimic the operating conditions the transistors will have in circuit? the ZTX will be connected through their bases, so I think theres something on it to ( compensate) allow for that? I've used the setting in the manual but it doesnt cover testing power transistors as far as I can see? I know about the pulse feature so the DUT isn't subject to heating.
Many thanks
Joe