Recent Posts

1

Repair / Re: Tektronix 2225 vertical display problem

« Last post by AndrewEp17 on Today at 02:05:00 am »

Possibly a burnt input resistor. Some other guy somewhere here had a burnt input resistor on a 22xx series scope. It's soldered directly on the BNC so not hard to check.

i checked both channels and the resistors are the correct value but one looked a little dark and the paint was chipped so i will probably replace those as well. thanks for the advice!

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Repair / Re: Tektronix 2225 vertical display problem

« Last post by AndrewEp17 on Today at 02:02:04 am »

Hi there, do you have another scope, or signal tracer ? Here's a service manual with schematic's. I'd try and trace the signal into the attenuation/pre-amp section, and then the main vertical pre-amp and driver section.

I have no idea what this site is, but the 216page 14MB pdf is too big to upload.
http://bee.mif.pg.gda.pl/ciasteczkowypotwor/Tek/2225%20SM.pdf

I have a rigol ds2302a and I actually ended up fixing it by doing that! I looked at the schematics before but i didn't think of tracing the input signal until you said that haha. i looked at those parts of the schematic and i knew it probably wasn't going to be in one of the preamps because both channels had the same issue. So I ended up tracing it back to Q256 in the vertical amplifier which is the last transistor the signal goes into to drive the deflection plate of the CRT. I removed Q256 and Q257 from the circuit, both were 2N3866. i thought i was going to to have to buy more until i saw that the emitter pin had broken off probably from heat and I tested them with a meter and they seemed to be good so i decided to solder a wire directly to the metal case of the transistors and soldered them to the bottom of the board and that ended up fixing it! thanks for the advice!

also i will put them back in correctly i only soldered them to the bottom to test them

3

Projects, Designs, and Technical Stuff / Re: Brinking Light pattern for maximum attention distance at night

« Last post by BrianHG on Today at 02:01:27 am »

Example mid power one: Mid power Xenon  (Strong enough to instantly flash a sheet of paper into flames and burn your skin)

pah a mere 8kw,you really need 10x that to get noticed.https://hungaroflash.com/termekek/t-light-pro-85000w/

Now we are talking...

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Projects, Designs, and Technical Stuff / Re: Brinking Light pattern for maximum attention distance at night

« Last post by themadhippy on Today at 02:00:11 am »

Example mid power one: Mid power Xenon  (Strong enough to instantly flash a sheet of paper into flames and burn your skin)

pah a mere 8kw,you really need 10x that to get noticed.https://hungaroflash.com/termekek/t-light-pro-85000w/

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General Technical Chat / Re: JWST Takes a new photo of the horse head nebula

« Last post by JustMeHere on Today at 01:54:14 am »

Amazing how many galaxies are visible in this image!

I can only speculate at the field of vision in the NIRI cam.  Probably smaller than a pin head with an outstretched arm.  Hubble images are, supposedly, the size of half a thumb nail at arm's length.

Just looked it up....it has 2 x 2.2^2 arc minute cameras.   The moon is about 30. 

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Test Equipment / Re: Siglent Bench DMMs SDM3065X, SDM3055 and SDM3045X

« Last post by klausES on Today at 01:51:35 am »

Hello.
The mere exchanging for a better fan alone was not enough for me.
My solution to the original fan that was too loud continued.
My focus was on the temperatures evenly whether summer or winter to keep value on the same value, which made a regulation necessary.

A little insight I meant
https://www.eevblog.com/forum/testgear/siglent-sdm-and-sdg-series-maximum-silent/msg2979466/#msg2979466

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FPGA / Re: Hyperram to MAX10 (with no DQS shift)

« Last post by LootMaster on Today at 01:51:04 am »

Ok please confirm that this VCCIO +0.3v is legit info because I'm gonna make the pcb like this.

If I understand corectly, in quartus the VCCIO that is included in the colored square of the IO baank is that IO bank's respective VCCIO ( well duh). So heres is my circuit, please confirm.

As for availability, this is the situation. I believe going forward 3.3v will get phased out.

Brian, ca you answer your pm, I have a circuit I would liek you to review, a pcb, its beautiful, its powerful, the future of canada's economy revolves around something like this. Please help, my hero. Help me make a cool robot before the return of Jesus and the destruction of Canada.

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Projects, Designs, and Technical Stuff / Re: Homebrew Lock-In Amplifier

« Last post by mawyatt on Today at 01:49:22 am »

The PPM will naturally create I and Q outputs. The 8 phase version seems to be the "sweet spot" wrt to performance vs complexity.

Best,

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Repair / Re: MCH-305D-II bench power supply can't change current on one channel

« Last post by teatime on Today at 01:49:06 am »

Attached please find the schematic of this power supply.

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Repair / Re: MCH-305D-II bench power supply can't change current on one channel

« Last post by teatime on Today at 01:45:19 am »

The current potentiometer maybe aged.
you can try to replace a new one.