A working device and a broken device

[rego21]

Hello,

I have a question that that's been on my mind recently, If I had two of the same device one that works and the other one which is faulty would it be possible to always know what the fault is just by comparing the two devices?? would it be similar to having a schematic?

 

[picbits]

Not always and if you don't know what you're doing, you could rapidly end up with two non working devices.

 

[gophert]

Hello,

I have a question that that's been on my mind recently, If I had two of the same device one that works and the other one which is faulty would it be possible to always know what the fault is just by comparing the two devices?? would it be similar to having a schematic?

no.

 

[Nigel Goodwin]

From a repair point of view it 'can' be helpful - as you can compare voltages and signals across the two (this is an advantage of a stereo amplifier, you can compare the two channels).

However, knowing where to compare voltages and signals still really needs a circuit - and an invaluable skill is learning to draw the circuit out, or at least the relevant part of it.

So having a known working unit is helpful, but not massively.

 

[KeepItSimpleStupid]

It makes a big difference if it's say an audio pre-amp or an e-beam evaporator or an electron microscope. I maintained both of the later devices. Both are very deadly. The e-beam has a 15 kV supply at 1.5 Amps.

 

[gophert]

It makes a big difference if it's say an audio pre-amp or an e-beam evaporator or an electron microscope. I maintained both of the later devices. Both are very deadly. The e-beam has a 15 kV supply at 1.5 Amps.

With 22KW of evaporator power, you should be able to teleport a Toad-sized animal in the 10 seconds of a typical Star Trek teleportation scene.

 

[KeepItSimpleStupid]

Yep. Power in is 3 phase 208 Amps. For the 3 source unit, power in was 3 phase 208 90 Amps. The last one was a mess, We bough tit at auction and alll of the wires attached to a hidden plug no-less were cut. they had no faith in me getting the unit to work. When all done, the sources had a manufacturer defect which would cost $3K each to buy new sources, I think. We chose not too. We just plugged it in. I think the 90 A had a disconnect.

Basically a BIG CRT tube with no CRT.

The x-ray diffaction unit power supply was 0-100 kV at 0.1 A, so 10 KW.

One system (non-ebeam) was fed 208 3 phase 200 amps. I know it was 200A, Not sure about the 3 phase.

It's wierd. The power for an entire house in a wall socket.

 

[KeepItSimpleStupid]

Somebody at work figured out how to distribute seven to nine 1200 W power supplies, some 120, some 208 and some 120-240. He mounted a breaker panel on the side of the rack and plugged it into the wall.

I worked on a way to distribute the outputs. The supplies were mostly 40V @ 30A, one was 200 W @ 120V or so.

 

[Nigel Goodwin]

It makes a big difference if it's say an audio pre-amp or an e-beam evaporator or an electron microscope. I maintained both of the later devices. Both are very deadly. The e-beam has a 15 kV supply at 1.5 Amps.

My son-in-law has had one added to his workload (he's a University Technician) - the previous guy in charge of it is retiring due to terminal cancer - makes me a bit concerned as to how safe the machine might be?.

 

[gophert]

My son-in-law has had one added to his workload (he's a University Technician) - the previous guy in charge of it is retiring due to terminal cancer - makes me a bit concerned as to how safe the machine might be?.

The machine is fine, it was all of the condensed nano-powders - vanadium, manganese, nickel, chromium, ... because, "hey, what's a little bit of toxic Nano-powder going to do me", said the sick guy.

 

[KeepItSimpleStupid]

My son-in-law has had one added to his workload (he's a University Technician) - the previous guy in charge of it is retiring due to terminal cancer - makes me a bit concerned as to how safe the machine might be?.

If it's an Airco-Temescal CV-8, I'm pretty experienced with it. It blew a transistor every year until I fixed it permanently. The schematics are online. We eventually acquired 3 and one fell off a truck which someone else repaired. The CV-8 has some systemic problems which can be fixed easily. I worked on a Telemark 3 source supply. It was basically put it back together after lots of wires were cut. The only other problem was the Hi-voltage regulator tube was out of it's socket.

 

[unclejed613]

If I had two of the same device one that works and the other one which is faulty would it be possible to always know what the fault is just by comparing the two devices?? would it be similar to having a schematic?

ok, we'll take a stereo receiver as an example, yes you can with an ohmmeter compare components in the working channel with the non-working channel, especially if the manufacturer laid out both channels identically, or in mirror image, but it's still best to work with a schematic whenever possible.