Hey guys,
I'd like some advice on how to diagnose the PSU for this device, and how to check if certain components are good or bad. Here are some photos:
So far I checked the fuses and also replaced one cracked capacitor but still doesn't work.
Help diagnosing an ultrasonic
-
Steve
- Posts: 3308
- Joined: 15 Sep 2017 11:49
Help diagnosing an ultrasonic
You do not have the required permissions to view the files attached to this post.
-
rubber_jonnie
- Site Admin

- Posts: 14903
- Joined: 17 Aug 2017 19:40
- Location: Essex
Re: Help diagnosing an ultrasonic
Well, I'm seeing large diodes, some transistors and probably MOSFETS and a bridge rectifier, oh and that IC.
You could check the diodes quite easily and probably get a datasheet for the FETs and make sure what input/output voltages they should have, tough you'd probably need to remove them to do so.
Do you have a component tester? they can be quite handy, though you'd need to remove the components from the board. You could also check the rectifier see if it's getting AC at the input and is pushing out DC, again, best get a datasheet.
The IC could probably be replaced quite cheaply too.
Whatever you do be damn sure to be careful and not get electrocuted?
I'm guessing you don't have a schematic?
You could check the diodes quite easily and probably get a datasheet for the FETs and make sure what input/output voltages they should have, tough you'd probably need to remove them to do so.
Do you have a component tester? they can be quite handy, though you'd need to remove the components from the board. You could also check the rectifier see if it's getting AC at the input and is pushing out DC, again, best get a datasheet.
The IC could probably be replaced quite cheaply too.
Whatever you do be damn sure to be careful and not get electrocuted?
I'm guessing you don't have a schematic?
Collector of many retro things!
800XL and 65XE both with Ultimate1MB,VBXL/XE & PokeyMax, SIDE3, SDrive Max, 2x 1010 cassette, 2x 1050 one with Happy mod, 3x 2600 Jr, 7800 and Lynx II
Approx 20 STs, including a 520 STM, 520 STFMs, 3x Mega ST, MSTE & 2x 32 Mhz boosted STEs
Plus the rest, totalling around 50 machines including a QL, 3x BBC Model B, Electron, Spectrums, ZX81 etc...
800XL and 65XE both with Ultimate1MB,VBXL/XE & PokeyMax, SIDE3, SDrive Max, 2x 1010 cassette, 2x 1050 one with Happy mod, 3x 2600 Jr, 7800 and Lynx II
Approx 20 STs, including a 520 STM, 520 STFMs, 3x Mega ST, MSTE & 2x 32 Mhz boosted STEs
Plus the rest, totalling around 50 machines including a QL, 3x BBC Model B, Electron, Spectrums, ZX81 etc...
-
Steve
- Posts: 3308
- Joined: 15 Sep 2017 11:49
Re: Help diagnosing an ultrasonic
Hmm yeah to be honest I am afraid to work on it because it is AC. I might contact Ultrawave and see how much it'd cost to just swap the board. I checked that IC and it's unobtanium, so the manufacturer of the machine is probably the only ones with stock.
-
rubber_jonnie
- Site Admin

- Posts: 14903
- Joined: 17 Aug 2017 19:40
- Location: Essex
Re: Help diagnosing an ultrasonic
If you can get the maker involved that is a good plan.Steve wrote: 24 May 2022 13:38 Hmm yeah to be honest I am afraid to work on it because it is AC. I might contact Ultrawave and see how much it'd cost to just swap the board. I checked that IC and it's unobtanium, so the manufacturer of the machine is probably the only ones with stock.
You can work safely with AC, but if you're 'not feeling it' then safer to not do so :)
Collector of many retro things!
800XL and 65XE both with Ultimate1MB,VBXL/XE & PokeyMax, SIDE3, SDrive Max, 2x 1010 cassette, 2x 1050 one with Happy mod, 3x 2600 Jr, 7800 and Lynx II
Approx 20 STs, including a 520 STM, 520 STFMs, 3x Mega ST, MSTE & 2x 32 Mhz boosted STEs
Plus the rest, totalling around 50 machines including a QL, 3x BBC Model B, Electron, Spectrums, ZX81 etc...
800XL and 65XE both with Ultimate1MB,VBXL/XE & PokeyMax, SIDE3, SDrive Max, 2x 1010 cassette, 2x 1050 one with Happy mod, 3x 2600 Jr, 7800 and Lynx II
Approx 20 STs, including a 520 STM, 520 STFMs, 3x Mega ST, MSTE & 2x 32 Mhz boosted STEs
Plus the rest, totalling around 50 machines including a QL, 3x BBC Model B, Electron, Spectrums, ZX81 etc...
-
bigbloke
- Posts: 37
- Joined: 25 Oct 2021 13:55
Re: Help diagnosing an ultrasonic
I spend all day finding components for work so this was an easy one: https://www.switchelectronics.co.uk/cd4093beSteve wrote: 24 May 2022 13:38 Hmm yeah to be honest I am afraid to work on it because it is AC. I might contact Ultrawave and see how much it'd cost to just swap the board. I checked that IC and it's unobtanium, so the manufacturer of the machine is probably the only ones with stock.
It's just a cmos quad nand gate, other manufacturers than Fujitsu still make these.
Good luck with the rest of the repair process, I'm unable to help fix PSUs - I have enough of my own to play with!
-
exxos
- Site Admin

- Posts: 28375
- Joined: 16 Aug 2017 23:19
- Location: UK
Re: Help diagnosing an ultrasonic
The 4093 ?Steve wrote: 24 May 2022 13:38 I checked that IC and it's unobtanium, so the manufacturer of the machine is probably the only ones with stock.
https://uk.farnell.com/texas-instrument ... dp/3120154
-
rubber_jonnie
- Site Admin

- Posts: 14903
- Joined: 17 Aug 2017 19:40
- Location: Essex
Re: Help diagnosing an ultrasonic
Plenty of the 4093 ICs on eBay too as well as Farnell, that is if you can't stand their excessive delivery charges for small items.Steve wrote: 24 May 2022 13:38 I checked that IC and it's unobtanium, so the manufacturer of the machine is probably the only ones with stock.
Collector of many retro things!
800XL and 65XE both with Ultimate1MB,VBXL/XE & PokeyMax, SIDE3, SDrive Max, 2x 1010 cassette, 2x 1050 one with Happy mod, 3x 2600 Jr, 7800 and Lynx II
Approx 20 STs, including a 520 STM, 520 STFMs, 3x Mega ST, MSTE & 2x 32 Mhz boosted STEs
Plus the rest, totalling around 50 machines including a QL, 3x BBC Model B, Electron, Spectrums, ZX81 etc...
800XL and 65XE both with Ultimate1MB,VBXL/XE & PokeyMax, SIDE3, SDrive Max, 2x 1010 cassette, 2x 1050 one with Happy mod, 3x 2600 Jr, 7800 and Lynx II
Approx 20 STs, including a 520 STM, 520 STFMs, 3x Mega ST, MSTE & 2x 32 Mhz boosted STEs
Plus the rest, totalling around 50 machines including a QL, 3x BBC Model B, Electron, Spectrums, ZX81 etc...
-
Steve
- Posts: 3308
- Joined: 15 Sep 2017 11:49
Re: Help diagnosing an ultrasonic
Thanks guys! I was reading the part number incorrectly. Ordered myself a couple of these chips. I'm happy to just try a few easy/cheap part replacements. Thx.
Who is online
Users browsing this forum: ClaudeBot and 2 guests