开云体育

On a tangent, I’ve been reading through the datasheet of the PFC IC. It’s a pretty interesting device. As it’s a critical current conduction mode controller, the switching frequency is variable

First thing, replace all the SMD electrolytic capacitors throughout the unit, on the processor board, acquisition board, and front panel (maybe the firmface board if fitted and caps are there too? I'm

The following photos have been uploaded to the Type 284 Repair Pictures ( /g/TekScopes/album?id=248421 ) photo album of the [email protected] group. * R133 Location-Edit.jpg (

Oh man, I think I have a big red pot on the front right of the inside face where the revised Fig. 6-25 shows R133, but had no idea what it was for. Thanks for pointing this out! Adam

Thanks Albert. Looks like Tek replaced 30k external pot with a 30k internal (R133) + 3k external (R132) pot. TD current would change over a wider range from part to part but once the unit is

Yes, I am looking at 070-0754-00, pulse generator (schematic sheet 2). But it must be a later version. It is available on the BAMA site. There is a relevant modification as well (apologies for the

The change from R133 to R132+R133 occurred at B04000. http://bama.edebris.com/manuals/tek/284/ Albert

Well, that's a great question. I've seen reference to "coarse bias" but assumed they meant R123, bias balance. My 284 seems to match 070-0754-00 schematics (i.e., there is no R133). The 070-0754-01

There is no R133 in 070-0754-00. Is there a revised schematic? Ozan

I repaired a TDS520 with exactly same error screen after repairing a (literally) burned power supply. In my case leaking electrolytic caps damaged a trace to U900 on acquisition board. Ozan

Adam, For your reference, I checked the voltages at J135/J145 in a working 284: Measured +- 11.8v (working with pulse output) Low limit: +-9.9v High limit +- 14.9v So the adjustment range using

With TD BIAS at mid point and assuming a linear pot, swing at Q120/125 should be about 20V*(11.1k // 30k)/(2.2k+11.2k//30k)=15.7V single ended but your scope shot shows ~ 13V. Low point is ~ 0V so the

Hi to all usual suspects here. You will maybe remember you helped me resurect my 7704A from decades of non working neglect. Thanks! Here is for me a new challenge. I did a large leap in time from the

Hi, I use a Topward 6306A (Linear design, Separate Voltage and Current Analog Meters, Dual 30V @ 6A, 5V @ 5A), Topward 6603D (Linear design, Separate Voltage and Current Digital Meters, Dual 60V @

On Thu, Dec 14, 2023 at 04:12 PM, Vince Geisler wrote: > > Jared, > > yes, as far as i can understand, Q5,6 are for for PFC. They step the 120vac > wall power to 400V. That part seems to work fine

The problem is entirely consistent with a bad snubber network, or else a leaky CR4 like someone else mentioned. IRFP450 is only specified for 500V(DS), so boosting to 400V is already operating pretty

I guess that I'm a little surprised that that nobody has mentioned this "Red 0-30V 2mA-3A" from ebay as a way to update old boat anchors. This design as supplied has some serious flaws but they are

I've done that when verifying TD functionality while troubleshooting some time-bases. Ozan suggested how to do it and it works very well. Sort of gratifying to watch that jump when the TD

Sorry - Just noticed your price target in a later post. The Aim-TTi MX models are going to be quite a bit more than $100-$150. -mark

Hi Adam My 284 isn't cooperative today, refused to produce an output pulse. Two days ago I think it started (after heating up somewhat with a f?hn) but then the scope broke down. (Extreme bright