Thank you for another great video! One minor note for someone trying to replicate the high frequency AC voltage measurement: The 34465A is specified for up to 300kHz, but most hand-held DMMs are much more limited, e. g. Fluke 179: 1kHz, Fluke 87V: 20 kHz, Brymen BM789: 100 kHz. An isolated oscilloscope (consider max. voltage) or a HV differential probe can help here. One more thing: Did you happen to measure the waveform/peak voltage at this cap afterwards? Would give some peace of mind that the selected capacitor with its voltage rating is properly chosen. (I'm pretty confident it is...)
Thanks for watching! Yes you need to know the limits of your test equipment. I did check the voltage and waveform across the ceramic surface mount capacitor. It is a 94 KHz very narrow spike waveform with the spikes going to about 5 volts and it is riding on 3 volts DC. Note this is voltage across the cap, not referenced to ground, measured with a Fluke 199C isolated ground scopemeter.
Often the switching power supplies require a minimum load on the “main” output. That is the one from where the controller gets its feedback. The other note or guess is that there could be a solder whisker at or under the capacitor that exhibited the low resistance. One more detail. My Dynaload has a current monitoring output from the built-in shunt. Yours is likely to also have one.
Yes some switchers do need a minimum load or they can't regulate properly. The data sheet for this model says that for less than 1 volt regulated output you need at least 500 mA. So for typical use at higher voltages as marked on the modules a minimum load isn't needed. Certain types of ceramic surface mount caps are prone to failing from stress as it cracks them or damages the structure since they have no flexible leads. There are surface mount caps designed to take flexing stress probably not what was used here. Yes the Dynaload has a current sample output. I recently did a video on another Dynaload model that needed repair ..you may be interested in seeing that.
This is a high-quality video. Lots of works and troubleshooting involved and efforts to show and educate us all. Love it and thank you so much.
Thank you for the compliment and I am happy to know you enjoyed the video and found it helpful.
The ceramic caps might be for ac coupling if that toroid is a gate drive transformer. I'd really be curious to see what control chip they're using.
Great diagnosis! Lambda made some great supplies
Thanks and yes they sure did make some quality heavy duty power supplies.
Great video and well done trouble shooting!
Thank you!
Really very helpful diagnosis !
Glad you found the video helpful!
Excellent !, I love your videos, thanks .
Thanks for watching and glad you are enjoying my videos!
Wow. Module is quite quality
Thank you for another great video! One minor note for someone trying to replicate the high frequency AC voltage measurement: The 34465A is specified for up to 300kHz, but most hand-held DMMs are much more limited, e. g. Fluke 179: 1kHz, Fluke 87V: 20 kHz, Brymen BM789: 100 kHz. An isolated oscilloscope (consider max. voltage) or a HV differential probe can help here.
One more thing: Did you happen to measure the waveform/peak voltage at this cap afterwards? Would give some peace of mind that the selected capacitor with its voltage rating is properly chosen. (I'm pretty confident it is...)
Thanks for watching! Yes you need to know the limits of your test equipment. I did check the voltage and waveform across the ceramic surface mount capacitor. It is a 94 KHz very narrow spike waveform with the spikes going to about 5 volts and it is riding on 3 volts DC. Note this is voltage across the cap, not referenced to ground, measured with a Fluke 199C isolated ground scopemeter.
Excellent ! How can I get my gfa 555 2 updated
Check out hoppesbrain.com/category/adcom/ for upgrades, modifications, parts, etc.
Often the switching power supplies require a minimum load on the “main” output. That is the one from where the controller gets its feedback. The other note or guess is that there could be a solder whisker at or under the capacitor that exhibited the low resistance. One more detail. My Dynaload has a current monitoring output from the built-in shunt. Yours is likely to also have one.
Yes some switchers do need a minimum load or they can't regulate properly. The data sheet for this model says that for less than 1 volt regulated output you need at least 500 mA. So for typical use at higher voltages as marked on the modules a minimum load isn't needed. Certain types of ceramic surface mount caps are prone to failing from stress as it cracks them or damages the structure since they have no flexible leads. There are surface mount caps designed to take flexing stress probably not what was used here. Yes the Dynaload has a current sample output. I recently did a video on another Dynaload model that needed repair ..you may be interested in seeing that.
capacitors stink when they blow up.