开云体育

More. You can check diodes by making differential measurements across the diode. I found two bad power diodes this way. You can do this measurement while the unit is in tic mode. I found the diodes

You need a load of about 50W, possibly equally shared between positive and negative outputs. Either on the raw voltages or after the regulator board. You need to check all caps and diodes on the

Hi Max, Well, I didn't say that the load MUST be distributed. For me reasons to do so were that I could use available 5 W and 10 W resistors and that I wasn't always sure about the maximum current an

To G?ran: OK, shorted pin 13 to ground. Still same result: the SMPS refuses to starts and ticks herratically. I've checked the signal across A and K of Q30 (the PUT): it fires up every 20 msec (I

In the archive there is another document "7k_PS_currents" describing typical loads, also scanned by Zenith. In my case the total load was 50W. I connected a number of power resistors to the various LV

Hi Max, From my own experiments with a 7704A SMPS I remember that it needed a much heavier load for proper operation. I tried with loads on the HV outputs and also with loads on the raw rectified

Thanks for the tip!

That’s what mine looks like.

In the archive there is a document scanned by Zenith, a specification 155-0067-02, pdf. For pin 13 there shall be two conditions: Logic "0": 0.0 - 0.05 V Logic "1": 0.85 - 10 V Well, if you dare you

The "filter on" position is useless except for very low sweep speeds or manual scanning - not normal operation. I found the same sort of thing when I was refurbishing the switches (Deoxit-treatment)

Following the Goran suggestion, I've shorted to ground pin 2 (FAULT SENSE). The behavior was the same: random burst interspersed with single pulses. Probing with an oscilloscope the pin 13 (Current

Hi all, Interestingly, after acquiring the Pacific Measurements 1038 system, I found the Tekwiki had a reference regarding using the D10 and D11 mainframes. I noticed the D14 which I had wasn't noted

/g/TekScopes/album?id=89780&p=Created,,,20,2,0,0 This is what the display filter does to my screen

I've gotten this 7L5 worked over to where it is mechanically squared up and fits properly in the mainframe. It took a lot of blacksmithing and modifications, but it now looks good, and is apparently

Hi Nenad, I tend to disagree with your analysis. The feedback is not primarily intended to keep the base of Q36 at a constant DC level. Within limits Q36 doesn't care. The purpose is to have the

Hi, I worked on this PS in a 7904 some years ago. There are two overload conditions, over/under voltage and over current. Either shall turn the supply off. However, I think there is a third condition

I Have model 3 I can send you. What do you wan to pay? -- John

These scopes are not a good fit for a hack job if you want extended life. I recommend you get it to an experienced tech that understands these units and can make successful repairs without creating

When you replaced the bad capacitors, were the originals of the can style with several ground tabs? Did you restore all those ground connections by using caps of the same type, or otherwise restore

Ok, perhaps this i