The foreign object appears to be a bit of hay. Stored out in the barn? I use the same basic method for testing large electrolytic capacitors, especially bolt-in type (reads "expensive" or "hard to find"). As a test equipment geek who suffers from TAS, I use an HP 4282A Digital High Capacitance Meter that supplies DC up to 120 volts and has a leakage range of 1 microamp full scale. I have noted that with a good capacitor after the initial charge period the leakage current will fall slowly over the next few hours to very low levels. I suppose that could be considered "re-forming" - I call it thorough testing. Thank you for another interesting video, I am looking forward to the rest of the series. Regards, David
Very early capacitors used in valve (tube) electronics had two 'plates' which were normally formed using two sheets of foil separated by some sort of insulator. The entire roll was immersed in liquid electrolyte and when in use the foil developed a 'layer' on each side and this allowed the capacitor to work properly. When not in use the electrolyte seemed to wash this layer off and so the capacitors did not work very well until 're formed'. Generally they had very low capacitance and high leakage and could even develop shorts under high voltage. Modern capacitors work very differently but I think there is some carry over in expectations. I have never 'reformed' a modern capacitor. Some capacitors may improve a little when used for a time although some get a little worse but if a modern capacitor is low in capacitance or leaky then it should be replaced. Actually the same was true of the old electrolytics as well but they did sometimes reform to a certain extent. If you watch the current in the video you will see that it drops to less than 1mA within a few seconds as the caps charge and it stays there. I see that in almost every modern capacitor I test, the rest are faulty. However if people want to 'reform' capacitors then they should go for it.
From the video it looks like the bigger caps are pushing out the pressure relief cuts in the top and I think a lot of people would replace them just based on that. But I guess that's just how they look?
As I say in the video the method I use depends on what contamination I need to remove. This board was only covered in dust and dirt so was easy to clean but some require other methods,
I would have replaced the caps anyway, however - so glad you showed me that this isn't always necessary. Great stuff as always!
What’s interesting is the rs-422 is made to go along with the TS-816/40
It’s a multiuser Z80 computer
Jerry, what cleaning process do you use to remove electrolyte that has leaked onto a board, like on your power supply board?
The foreign object appears to be a bit of hay. Stored out in the barn? I use the same basic method for testing large electrolytic capacitors, especially bolt-in type (reads "expensive" or "hard to find"). As a test equipment geek who suffers from TAS, I use an HP 4282A Digital High Capacitance Meter that supplies DC up to 120 volts and has a leakage range of 1 microamp full scale. I have noted that with a good capacitor after the initial charge period the leakage current will fall slowly over the next few hours to very low levels. I suppose that could be considered "re-forming" - I call it thorough testing. Thank you for another interesting video, I am looking forward to the rest of the series. Regards, David
Very early capacitors used in valve (tube) electronics had two 'plates' which were normally formed using two sheets of foil separated by some sort of insulator. The entire roll was immersed in liquid electrolyte and when in use the foil developed a 'layer' on each side and this allowed the capacitor to work properly. When not in use the electrolyte seemed to wash this layer off and so the capacitors did not work very well until 're formed'. Generally they had very low capacitance and high leakage and could even develop shorts under high voltage. Modern capacitors work very differently but I think there is some carry over in expectations. I have never 'reformed' a modern capacitor. Some capacitors may improve a little when used for a time although some get a little worse but if a modern capacitor is low in capacitance or leaky then it should be replaced. Actually the same was true of the old electrolytics as well but they did sometimes reform to a certain extent. If you watch the current in the video you will see that it drops to less than 1mA within a few seconds as the caps charge and it stays there. I see that in almost every modern capacitor I test, the rest are faulty. However if people want to 'reform' capacitors then they should go for it.
Forgot to say, the object was a bit of sealant from the tube band.
From the video it looks like the bigger caps are pushing out the pressure relief cuts in the top and I think a lot of people would replace them just based on that. But I guess that's just how they look?
No that is just the style of the capacitors. They have offset segments but the tops are totally flat.
Tried the cleaning method for my board but it sadly didn't work.
As I say in the video the method I use depends on what contamination I need to remove. This board was only covered in dust and dirt so was easy to clean but some require other methods,
@@JerryWalker001 now i snapped my fingers twice more and the board is clean. thanks!
@@8o86 You need to be careful. If you snap your fingers twice it can make it dirty again.