Hantech 6022 scope - UK Vintage Radio Repair and Restoration Discussion Forum

NorfolkDaveUK · 9th Sep 2018, 9:31 am

Hi ,
I have a hantech usb scope and the other night I was working on a reel to reel , NOT with the scope but it was plugged into the USB of my PC. I was testing some voltages with my MM and managed to accidentially short a mains supply tripping the house fuses ...ooops .

Anyway , the scope was not in anyway connected to the work I was doing , but , on powering everyhing back up my pc came up with a usb over amp warning and the scope wouldnt power on . So I took it apart and it has blown the input diode . So I swapped that out and now it powers on again , but , i have no probe action at all and its giving me a constant 5v dc reading on BOTH channels . I`m assuming this is coming from the power input. Any idea how I may trace this problem , obviously , without a scope ?

Cheers

MrBungle · 9th Sep 2018, 9:52 am

That’s probably completely dead and BER as the diodes blew. That finished the buffer off that comes after it and probably the programmable gain amplifier and ADC after it. If you look at the schematic there’s virtually no protection on them. It jumped over the compensation cap (looking at it, probably 50v rated max) and that leaves a couple of resistors and the weakest diode clamp ever to have existed as protection. Not sure if it’s a 2 or 4 layer board but if it’s the latter there’s probably damage you can’t see as well.

I would throw it away. I know that’s contrary to common advice here but the chances you’ll fix everything here even if you step through the signal chain without incurring more cost than a new one is low.

It’s worth investing in an isolated HV probe for this stuff or hiding the mains stuff away carefully. Scopes are fragile.

If this was connected to the PC it would have probably taken that out as well (!). One reason I refuse to use USB scopes.

NorfolkDaveUK · 9th Sep 2018, 10:19 am

It was connected to a PC and I wasnt using it at the time . lol I was using my multi meter and clamping a ground in , wasn`t paying attention and it the power switch ,.lol . oops . The house tripped , when everything came back on the only thing that flaked was my scope . I`m going to replace it with a stand alone . I liked the usb because it wasn`t a desk hogger and i dont have the cash for a digital with the readouts this one had , I liked this one because it gave you the readout of rms / p to p , mv , etc etc , don`t suppose it was paticulatly accurate but its more accurate than counting squares i think . any way , its going in the bin I had a bit of a play with it but the whole thing is just toast . so new one it is .

MrBungle · 9th Sep 2018, 11:13 am

Yeah we've all done it. I blew up a couple of attenuators in a Tek 465 a couple of months back doing something similar. Fortunately it didn't go past that!

Worth keeping eyes peeled for second hand digital standalone units. I picked up a 60MHz Tektronix TDS210 digital scope the other week for £60 that needed a couple of BNC connectors changed (£5 from RS). Works perfectly, has all the measurement functions built in etc. Lots of bargains out there; just have to wait in the shadows and pounce on them.

NorfolkDaveUK · 9th Sep 2018, 12:50 pm

Oh totally , thats how I get 95% of my reel to reel , lol . Patients is the #1 tool in this game .lol .

9th Sep 2018, 9:52 am	#2
MrBungle Dekatron Join Date: Jun 2016 Location: London, UK. Posts: 3,687	Re: Hantech 6022 scope That’s probably completely dead and BER as the diodes blew. That finished the buffer off that comes after it and probably the programmable gain amplifier and ADC after it. If you look at the schematic there’s virtually no protection on them. It jumped over the compensation cap (looking at it, probably 50v rated max) and that leaves a couple of resistors and the weakest diode clamp ever to have existed as protection. Not sure if it’s a 2 or 4 layer board but if it’s the latter there’s probably damage you can’t see as well. I would throw it away. I know that’s contrary to common advice here but the chances you’ll fix everything here even if you step through the signal chain without incurring more cost than a new one is low. It’s worth investing in an isolated HV probe for this stuff or hiding the mains stuff away carefully. Scopes are fragile. If this was connected to the PC it would have probably taken that out as well (!). One reason I refuse to use USB scopes.

9th Sep 2018, 10:19 am	#3
NorfolkDaveUK Banned Join Date: May 2018 Location: Norwich, Norfolk, UK. Posts: 605	Re: Hantech 6022 scope It was connected to a PC and I wasnt using it at the time . lol I was using my multi meter and clamping a ground in , wasn`t paying attention and it the power switch ,.lol . oops . The house tripped , when everything came back on the only thing that flaked was my scope . I`m going to replace it with a stand alone . I liked the usb because it wasn`t a desk hogger and i dont have the cash for a digital with the readouts this one had , I liked this one because it gave you the readout of rms / p to p , mv , etc etc , don`t suppose it was paticulatly accurate but its more accurate than counting squares i think . any way , its going in the bin I had a bit of a play with it but the whole thing is just toast . so new one it is .

9th Sep 2018, 11:13 am	#4
MrBungle Dekatron Join Date: Jun 2016 Location: London, UK. Posts: 3,687	Re: Hantech 6022 scope Yeah we've all done it. I blew up a couple of attenuators in a Tek 465 a couple of months back doing something similar. Fortunately it didn't go past that! Worth keeping eyes peeled for second hand digital standalone units. I picked up a 60MHz Tektronix TDS210 digital scope the other week for £60 that needed a couple of BNC connectors changed (£5 from RS). Works perfectly, has all the measurement functions built in etc. Lots of bargains out there; just have to wait in the shadows and pounce on them.

9th Sep 2018, 12:50 pm	#5
NorfolkDaveUK Banned Join Date: May 2018 Location: Norwich, Norfolk, UK. Posts: 605	Re: Hantech 6022 scope Oh totally , thats how I get 95% of my reel to reel , lol . Patients is the #1 tool in this game .lol .

9th Sep 2018, 9:31 am	#1
NorfolkDaveUK Banned Join Date: May 2018 Location: Norwich, Norfolk, UK. Posts: 605	Hantech 6022 scope Hi , I have a hantech usb scope and the other night I was working on a reel to reel , NOT with the scope but it was plugged into the USB of my PC. I was testing some voltages with my MM and managed to accidentially short a mains supply tripping the house fuses ...ooops . Anyway , the scope was not in anyway connected to the work I was doing , but , on powering everyhing back up my pc came up with a usb over amp warning and the scope wouldnt power on . So I took it apart and it has blown the input diode . So I swapped that out and now it powers on again , but , i have no probe action at all and its giving me a constant 5v dc reading on BOTH channels . I`m assuming this is coming from the power input. Any idea how I may trace this problem , obviously , without a scope ? Cheers