Search found 1306 matches
- Sun Apr 21, 2024 2:17 pm
- Forum: The Off-Topic Section
- Topic: PSU Primary side issue (non QL)
- Replies: 12
- Views: 254
Re: PSU Primary side issue (non QL)
It should stay triggered once you have raised the gate above the cathode voltage, and only reset once the current flow in the Anode to Cathode circuit has gone close to zero. The resistance reading between gate and cathode seems very low, it's normally equivalent to a diode, and as it's a thyristor ...
- Sat Apr 20, 2024 9:06 pm
- Forum: The Off-Topic Section
- Topic: PSU Primary side issue (non QL)
- Replies: 12
- Views: 254
Re: PSU Primary side issue (non QL)
If you have a multimeter with a DC input voltage rating of 500v or higher - you should be able to measure across the main capacitor - on DC voltage range - you should see some 350-400V. You could also check the stripe (cathode) side of the rectifiers on the secondary side - these should give some in...
- Sat Apr 20, 2024 5:31 pm
- Forum: The Off-Topic Section
- Topic: PSU Primary side issue (non QL)
- Replies: 12
- Views: 254
Re: PSU Primary side issue (non QL)
I think the wave forms and voltages may not read well on a multimeter. A scope will be the best way to read these voltages - assuming your probes and or scope inputs have the correct rating to check these - as you are dealing with quite high voltages here!
- Sat Apr 20, 2024 4:59 pm
- Forum: The Off-Topic Section
- Topic: PSU Primary side issue (non QL)
- Replies: 12
- Views: 254
Re: PSU Primary side issue (non QL)
Yes - provided the main capacitor on the primary side is ok, and the bridge rectifier - you should see the full wave voltage from the mains across it - so it will around 380-400v - for a 230/240 V mains supply. It's not that critical as the power supply works down to 110V by the looks of it. The cap...
- Sat Apr 20, 2024 4:45 pm
- Forum: The Off-Topic Section
- Topic: PSU Primary side issue (non QL)
- Replies: 12
- Views: 254
Re: PSU Primary side issue (non QL)
Looks like the 12V output from the PSU is used to regulate the PSU primary circuit, and the 5V circuit is further regulated by another IC, and also has a crowbar circuit across the input to that IC. Full service manual here: https://elektrotanya.com/grundig_gv280s-vpt,ft,t_vcr_sm.pdf/download.html#dl
- Sat Apr 20, 2024 4:29 pm
- Forum: The Off-Topic Section
- Topic: PSU Primary side issue (non QL)
- Replies: 12
- Views: 254
Re: PSU Primary side issue (non QL)
Do you have the service manual for it? Those circled numbers probably have expected waveforms or voltages to measure on the primary side, so if they are ok, the issue is likely on the secondary side of it. It's rare but not impossible for rectifiers on the secondary side to fail, which will obviousl...
- Tue Apr 09, 2024 3:45 pm
- Forum: The Off-Topic Section
- Topic: The Victorian Age
- Replies: 5
- Views: 249
Re: The Victorian Age
Back then Video hadn't even been born, so the Radio star was safe
- Sun Apr 07, 2024 5:11 pm
- Forum: The Off-Topic Section
- Topic: Happy Birthday!
- Replies: 437
- Views: 219481
Re: Happy Birthday!
Happy Birthday - enjoy the vino
- Thu Mar 21, 2024 9:04 am
- Forum: The Off-Topic Section
- Topic: Royal Mail Delays
- Replies: 6
- Views: 174
Re: Royal Mail Delays
To be fair to them - I've had something stuck at "langley" and it was down to customs check delays - so although it appeared to indicate RM had my parcel - it had not been officially released to them. I hate the fact that the tracking from either side doesn't tell you what our lovely HMRC ...
Re: RTC Query
esp32_ser.jpgHey Pr0f ; Someone was way ahead of me :D Anyway its great to try to program such nice connection. And one can make your own preferences. I do like the lilygo products though - and there is probably a lot more this could potentially offer - would be interesting to see how well it works...