Let's made a PC-base metal detector with usb interface !!!

[Aziz]

Sad News

Hi,

my oscilloscope died today (obviously died due to transportation) . Sadly, I couldn't check the latest ideas. Well, another big challenge to get a working device. I don't think, I can repair it. So everything will be delayed.

Aziz

[Mechanic]

.....

I don't think, I can repair it.

Aziz

Unless the tube is broken, I'm sure you can

Good luck

Cheers Mick

[WM6]

Hi,

my oscilloscope died today (obviously died due to transportation) . Sadly, I couldn't check the latest ideas. Well, another big challenge to get a working device. I don't think, I can repair it. So everything will be delayed.

Aziz

Which scope Aziz? Your Tektronix? Was it memory type?

As Mechanic say, if CRT tube is not broken, then if it was due transportation, usually only some lose contact happen.

Worth to open it, clean it and fix again all mowing parts (slots, IC in sockets, CRT socket, valves) and probably it will start like new. Look at Car spare parts for Electrical components cleaner spray of Sonax or something like this: http://www.amazon.de/KONTAKT-CHEMIE-.../dp/B001H0XLVC

[Aziz]

Well,

I have changed the fuse and it break again. The transformer is getting very hot and is not looking good too (after shorting the fuse). Seems to be a serious power supply problem.

That's not good. I'll have to look for another one on ebay soon.
Anyway, for some dumb measurements, I can still use my sound card scope.

Aziz

[WM6]

Well,

I have changed the fuse and it break again. The transformer is getting very hot and is not looking good too (after shorting the fuse). Seems to be a serious power supply problem.

That's not good. I'll have to look for another one on ebay soon.
Anyway, for some dumb measurements, I can still use my sound card scope.

Aziz

Bad, but you can still use it as coffee heater.

[Aziz]

Hi all,

yes it seems, the fault is in the power supply section. +/-5V and +32V not present actually (mV range). A very hot getting bridge rectifier is one of the suspected candidates. I'll check the transformer and the linear regulator power NPN transistors tomorrow.

Fortunatelly, I have the schematics of the device. This will definitely help to repair it.
Cheers,
Aziz

[WM6]

Hi all,

yes it seems, the fault is in the power supply section. +/-5V and +32V not present actually (mV range). A very hot getting bridge rectifier is one of the suspected candidates. I'll check the transformer and the linear regulator power NPN transistors tomorrow.

Fortunatelly, I have the schematics of the device. This will definitely help to repair it.
Cheers,
Aziz

Good luck with repair Aziz.

[Aziz]

Good news:

The fault is localised: The 32 V bridge rectifier so far (smoking and getting really hot, I have burnt my finger). That should be repaired really easy. I hope.

Aziz

[WM6]

Good news:

The fault is localised: The 32 V bridge rectifier so far (smoking and getting really hot, I have burnt my finger). That should be repaired really easy. I hope.

Aziz

Before final new bridge connection, check circuit after bridge on shorts to avoid fault repetition.

[Aziz]

Before final new bridge connection, check circuit after bridge on shorts to avoid fault repetition.

Yes, sure. Two diodes of the bridge rectifier seems to be damaged. It's shorting the AC input line. That's the reason, why the transformator get's hot too. And there is no +/-5V regulation without the +32 V line.

I can't get the damaged bridge rectifier. I have to build my own with four power diodes. (200V/1.5A specs)

I hope, the power transistor's are not damaged too. They are difficult to get.

Aziz

[Aziz]

Good News

Hi all,

I finally repaired my oscilloscope . I am very glad. Yes, it was the high voltage full bridge rectifier (200V/1.5A). I took four UF5404 (400V/3A) and made a discrete bridge rectifier. However, these diodes were the only nearest ones I have found in my box.

Thank you all in encouraging me not to give up.
Cheers,

Aziz

[Mechanic]

G'day Aziz,

Good news! I'm very glad you were able to get it going again. I knew you could do that

I find when that sort of thing happens that you go through an initial stage of not being very happy about it and after that I just accept it and start to work through it! On Christmas eve my car broke down in the bush. One of my solenoids for the gas system had gone open cct. I had an 8mm spanner and a flat screwdriver, my pick ad some wire from one of my detector chargers. After about an hour of just trying to start it and getting really p!ssed off I ended up pulling the solenoid off, unwinding it as the wire that went to the middle had broken. So I then set about rewinding it with a new tail out from the middle. But all was not over yet! My gas convertor had filled with coolant So I had to get to town to buy some spanners and sealant as I was expecting to have to do some bush surgery on the converter! Luckily once I was able to drain the gas compartments in the converter the car started, so I just put some coolant stop leak in and all is now good!



Cheers Mick

[Tinkerer]

At least you had a good mechanic at hand!!!!!!

I wish you ALL a happy new year.

Tinkerer

[WM6]

Hi all,

I finally repaired my oscilloscope . I am very glad.

Aziz

Congratulation Aziz.

Now you can open old scope repair service. I have one Tektronix 475 suddenly stop working for repair.

[Aziz]

Strange Things Happened

Hi all,

the repair topic has not been finished yet. Really strange things happened to my PC last days. The CPU fan got louder and the PC got slower. My software did not run correctly.
It did but very very slow.

Trojan? Virus? Software bug?

The reason was, that the CPU fan was slightly disconnected from the CPU. The thermal increase of the CPU speed up the CPU fan but it did not cool it down enough. As a result, the CPU has slowed the clock rate not to blow up the CPU (it even stopped working). I am glad to have an Intel CPU. I know, some other CPU would go up in smoke & fire.

The CPU fan fixing arrangement is due to aging broken (plastic). Well, I have repaired it provisional.

But my Tektronix is running better than ever. It seems, that the fault has existed a long time as the display brightness varied sometimes (one of the fault diodes of the bridge rectifier must have caused this).

------------

Project state: I need an inductivity meter right now
Project budget: the tide is out (bankrupt)

I am thinking of to make one of those cheap sound-card RLC meters (impedance meter) rather than spending at least 100 EUR for an inductivity meter. I have found many interesting sources for this little project.
Cheers,

Aziz