TSP

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Жыл бұрын

In this episode Shahriar takes a look at a non-functional Fluke 5450A resistance calibrator box. The unit is equipped with a wide range of resistors ranging from 1-Ohm to 100-MOhm some of which are 0.005% tolerance. The instrument powers on and shows a single LED on the front panel without any other activity.
Upon further inspection it becomes clear that there are no other activities from the main CPU despite the clock signal being present. A replacement CPU returns the unit to normal front-panel operation. The analog board also has two blown fuses which may be the result of a in-rush event. After fuse replacement the analog relay arrays also function. The unit is measured against a Keysight 3458A 8.5-digit multimeter and shows remarkable accuracy despite its age.
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Пікірлер: 71

@tomking6006 Жыл бұрын

One repairer I watch (I can't remember exactly who, but it may be Marco Reps) always takes out the eeproms and backs them up which seems like a very sound idea.

@silverXnoise Жыл бұрын

Love xDevs. Such a contribution to modern EE enthusiasts. Also, Ilia’s videos are like yours-a masterclass in top-notch engineering. Thanks to you both for sharing so much knowledge.

@EEVblog Жыл бұрын

Nice! IIRC my unit was a bit out compared with my 6.5 digit meter at the time. Might have to reevaluate it.

@kuglepen64 Жыл бұрын

Some of the PPMs escaped. Don’t tell Marco Reps.

@OctavMandru Жыл бұрын

Shariar, it looks almost too easy. It's so refreshing to see this, it really makes us plaebeians think we could have it easy, as well.

@amptechron Жыл бұрын

Always entertaining and informative. Thanks for a great channel!

@djjackson2200 Жыл бұрын

I love when your channel shows up on my notifications. Thanks for the awesome content!

@Edisson. Жыл бұрын

Hi, great catch again, whenever I've bought older measuring equipment on Ebay it's been a service massacre except for the HP 427A and 209A - it suffered in shipping and the slot connector for the power supply board cracked. This catch belongs to the WOW category 😁, I would be quite interested in the process of damage to the circuit for the relay power supply. My thinking is that the cpu got damaged and sent incorrect data to control the relay and it overloaded the power circuit, I would definitely do a deep relay check.

@dosgos Жыл бұрын

Mesmerizing relay action. I learned a lot in this short video!

@__--JY-Moe--__ Жыл бұрын

by digital ! the sexiest machines ever made! thanks 4 educating me, now I can fix the spaceshuttle! cheers!

@IanScottJohnston Жыл бұрын

Leave the 3458A powered 24/7 (30w approx.) if you aren't already, and perform an ACAL after a few days, then weeks, then months whilst doing some tests in between. It worked wonders for mine.

@randylemn Жыл бұрын

The missing chip is not used in the 5450A, The same CPU board was used in the 8520A and 8520A-PRT. Before you go and calibrate the unit as it has been sitting a while you should exercise the relays. Also when you do the calibration you will want to use the rear terminals.

@RyanUptonInnovator Жыл бұрын

Great video.

@buildstoys Жыл бұрын

Love the repair videos!

@TomStorey96 Жыл бұрын

Regarding uncovered EPROMs, I've been doing a bit of an experiment over the past year. I left a couple of them out to see what effect ambient and direct sunlight would have on the contents.

@t1d100 Жыл бұрын

Nice!

@benedienst Жыл бұрын

We still have the 5450A in operation at Fluke. The dry current relais in it are a bit troublesome as they develop instability with time. Also the high ohm reed relais in "newer" units which are plastic encased become leaky.

@ivanr5315 Жыл бұрын

Very good video! Might be worth saving a copy of the eproms content just in case they ever become corrupted (assuming that they are socketed)

@the8bitpc_805 Жыл бұрын

Nice job.

@davidv1289 Жыл бұрын

The large chip used for IEEE-488 support is a MC68488, a purpose built PIO chip designed by Motorola for the 6800 series microprocessors. It handles most of the bus handshaking and data transfer operations. Interestingly, it cannot drive the bus directly instead requiring separate bus transmitter/receiver chips. The MC3447 was the chip originally used for this purpose.