What's this please? (Component Advice)

[djos]

Murata DSS1 series for example?

Cheers, I’ll look them up.

[Evan.Cornell]

Two for ID:

• MEAS 02BM10570
• H724

Both sensors of some sort, I believe.

[PA0PBZ]

The hole suggests air pressure?

[Mr.B]

Or microphone?

[gamalot]

Two for ID:

• MEAS 02BM10570
• H724

Both sensors of some sort, I believe.

The first one is MS5637 pressure sensor from TE.

https://www.te.com/commerce/DocumentDelivery/DDEController?Action=showdoc&DocId=Data+Sheet%7FMS5637-02BA03%7FB4%7Fpdf%7FEnglish%7FENG_DS_MS5637-02BA03_B4.pdf%7FCAT-BLPS0037

[FrisscoCBR]

Hello, i am new hereee,can anyone tell me what this GAS1 component is, i have NEVER seen this reference designator beafore! Hope someone knows! Tnx in advance!

[orbiter]

It's a Gas Discharge Tube

[Cubdriver]

Hello, i am new hereee,can anyone tell me what this GAS1 component is, i have NEVER seen this reference designator beafore! Hope someone knows! Tnx in advance!

(Attachment Link)

Likely a gas discharge tube  used as a voltage clamp.  It's covered in heat shrink, so not as obvious.

https://m.littelfuse.com/~/media/electronics/product_catalogs/littelfuse_gdt_catalog.pdf.pdf  <---(See page 13)

-Pat

[peteb2]

Chasing down a datasheet for this SMD (MOSFET switches?). I've buzzed out with diode function on my DMM that their purpose in life is to switch the 2 parallel rechargeable 18650 3.7V LiOn cells -ve terminals to the rest of the circuit, (the +ve terminals are already permanently mechanically joined.

Can't find anything for "3130 U354".... any info truly appreciated.

[PA0PBZ]

https://datasheet.lcsc.com/szlcsc/2001131003_Shikues-BRCL3130ME_C475652.pdf

[bsudbrink]

Not so much a "what's this" as a "have you seen"...

A company called "Parasitic Engineering" sold various kits to improve the original Altair 8800 computer.  One of their kits was a "fix" to the clock generation circuit for the CPU:

https://deramp.com/downloads/altair/hardware/altair_8800_computer/Parasitic%20Clock%20Mod.pdf

If you don't want to be bothered to click through, it describes a chip, that they call a 94618, that is roughly pin compatible with a 74123 but is higher precision and has built in temperature compensation and schmidt triggered inputs.  My google-fu is coming up empty.  I'd appreciate any reference.  A manufacturer, a call out in a cross reference list, anything.  A picture would be wonderful and if you had one for sale...

[rsjsouza]

Some more modern implementations of the 74123 device have schmitt trigger inputs and temperature compensation (I didn't check the overall precision).

The CD74HC123 has schmitt triggers. I couldn't find any reference about tempco.
The SN74LS123 claims to have "enough Schmitt hysteresis to ensure jitter-free triggering from the B input with transition rates as slow as 0.1 millivolt per nanosecond.". This app note mentions it has temperature compensation.

Perhaps one of these options could help?

[PA0PBZ]

If I read the pdf correctly the circuit is to generate the correct clock signals even when the 2MHz crystal decides to oscillate at 6MHz. It looks easier to just get a better quality crystal. There is totally no info on a 94618, so maybe they relabeled something less expensive? You can't use a *123 here because that is retriggerable.

[rsjsouza]

You can't use a *123 here because that is retriggerable.

I noticed that after I posted (I didn't open the doc prior to my posting).

Perhaps the SN74LS221 then? Temperature stability, schmitt trigger inputs, pinout and non-retriggerable...

Other reference from NSC: AN-366.

[bsudbrink]

I appreciate the replies so far, except that I'm looking for this component for historical reasons.  I agree that nowadays there are much better options for correcting the problem.  I'd like to assemble a "replica" of the original kit.  It would never actually be used.  I guess that makes me a little bit of a chip collector (arg!), something I dislike.  I like everything in my collection to work.  No insects stuck on pins.  But, in this one case (actually, I can think of a couple more) I'll make an exception so that I can point to it and tell people "this is how you fixed bugs back in the day."  I could just take j-random-dip-package and paint "94618" on it I suppose...

[bsudbrink]

I was able to get in touch with someone who has an Altair CPU board with the modifications.  They were installed and working "back in the day" and still work now.  Funnily enough, my comment about:

I could just take j-random-dip-package and paint "94618" on it I suppose...

looks to be about right.  See the attached image.  I'm hoping he will pull the chip from the socket and see whether there are any identifying marks on the underside.  I'm wondering if the chip is just a 74221.

[PA0PBZ]

I'm wondering if the chip is just a 74221.

See my comment above:

There is totally no info on a 94618, so maybe they relabeled something less expensive?

[David Aurora]

I’m fixing up an HP 419A meter and one of the switches was knackered. The white plastic that holds the contacts was completely crumbling (luckily the others are fine).

Seems to be some kind of modular switch assembly where you can install the contacts you want, but so far I’m having no luck finding them. The contacts themselves are ok, I just need to replace the plastic strip (repair attempt already failed, and a large section was missing anyway.

Any tips on a manufacturer/model name/search term?

[Cubdriver]

The switch is HP part number 3101-0803, and it was made by Oak Manufacturing in Crystal Lake, IL.  My guess would be that it is a part custom made for HP.

Edit to add - best course might be to find a sheet of similar plastic and shape it to fit and manually add the needed contacts.

-Pat

[David Aurora]

The switch is HP part number 3101-0803, and it was made by Oak Manufacturing in Crystal Lake, IL.  My guess would be that it is a part custom made for HP.

Edit to add - best course might be to find a sheet of similar plastic and shape it to fit and manually add the needed contacts.

-Pat

Thanks mate! I tried looking up the part number I thought I had but got nowhere. Fabricobbling something myself was the backup plan, may still be the way to go. Shouldn't be too hard really, I was just feeling lazy and hoping those strips were a generic item still available that you could just install contacts into as you require (they seem to be, or at least seemed like they were at the time)

[djQUAN]

I have a lot of (fake) mosfets from a friend taken out of brand new off grid inverters. They still measure fine and are useable but I'm just curious as to what devices they actually are.

I did some measurements with the universal component tester for Vth and Ciss, kelvin connections for on on resistance and 100uA current limited supply for breakdown voltage at VGS=0V.

I also did some measurements with known original components for comparison and I'm leaning on an IRFZ44 or something slightly more beefy device than the Z44 for the fake 3205 and 1404 devices.

The IRFB4110 appear to be fakes but I have a limited mosfet vocabulary, maybe someone with a lot more experience with fets know what these devices are based on the measured specs.

[peteb2]

These China manufactured  semiconductors will likely be paralleled MOSFET dc Control to dim banks of LEDs but does anyone recognise them and have a link to a pdf etc... I have had a session on Google but no joy, here’s a picture of the cretins taken down the eyepiece of an old microscope with a knackered old iPhone 5S. TIA

[kjr18]

These China manufactured  semiconductors will likely be paralleled MOSFET dc Control to dim banks of LEDs but does anyone recognise them and have a link to a pdf etc... I have had a session on Google but no joy, here’s a picture of the cretins taken down the eyepiece of an old microscope with a knackered old iPhone 5S. TIA

Most likely they are SM4307 mosfets from sinopower. Here you have link to few datasheets.

[DreamWalking]

I have an unknown component and am unable to find any reference data, if anyone has knowledge of it, I would appreciate your sharing with me and any others that read this post.
The IC is in a SO8 packaging with two lines of information ..

SCA 106
CHMC S19

I believe the CHMC indicates it is a Chinese produced item as is the Kogan DAB radio that it is found in.
Hopefully I can buy one or find a substitute if I can get data about it.
Thank you.

[gamalot]

These China manufactured  semiconductors will likely be paralleled MOSFET dc Control to dim banks of LEDs but does anyone recognise them and have a link to a pdf etc... I have had a session on Google but no joy, here’s a picture of the cretins taken down the eyepiece of an old microscope with a knackered old iPhone 5S. TIA

Most likely they are SM4307 mosfets from sinopower. Here you have link to few datasheets.

Picture of SM4307 from Taobao