RE: Help Identifying Components
> -Original Message- > From: David Collins [mailto:davidkcolli...@gmail.com] > Sent: 24 December 2017 22:07 > To: r...@jarratt.me.uk; Rob Jarratt ; General > Discussion: On-Topic and Off-Topic Posts > Subject: Re: Help Identifying Components > > If you could wait, getting one of those ‘unknown component testers’ would help > you! > I have a fairly simple one actually, a Peak Atlas DCA55, but I would prefer to identify components without desoldering. If anyone would like to recommend a good tester that doesn't cost too much I would consider getting a better one. Regards Rob
Re: Help Identifying Components
If you could wait, getting one of those ‘unknown component testers’ would help you! David Collins > On 25 Dec 2017, at 5:27 am, Rob Jarratt via cctalk > wrote: > > I am continuing work to reverse engineer the schematic for my H7826 PSU. I > have removed one of the daughter cards in order to draw its schematic, but I > can't identify some of the surface mount components on it. I have posted a > picture of it here: > https://rjarratt.files.wordpress.com/2017/12/50-19530.jpg > > > > The ones I can't identify are: > > > > 1. The component with two wide pins that looks like an IC > approximately in the middle of the board. It is marked M106 (or it might be > AA106) and 91813 underneath. I think it may be a resistor, but I am not > sure. > > 2. Just to the right of this is another much thinner two-pin component > which is black on top with a kind of white notch. I have no idea at all what > this is. > > 3. The three 3-pin black components to the left of the first > component. Two of them are marked "2T L" (or is that "ZT L"?), one appears > to be marked "2X I" (letter "ih", not letter "el"). I guess they are > transistors, but they may not be of course, and I don't know their pinout. > > > > Any help with identifying what these are would be very helpful. > > > > Thanks > > > > Rob >
RE: Help Identifying Components
> > > > My guess is capacitors also. > > > Noting they are paralleling resistors, they're probably just noise/AC bypass, on > the order of 0.01 uF, and not overly consequential to understanding the basic > circuit. > > Again, one can draw it out with the above presumption and then assess > whether it makes sense or for alternative functions. > > > > This "SMD Code Book" should be of some value: > > > > http://www.sphere.bc.ca/download/smd-codebook.pdf > > I am indeed drawing it out. Whether I have drawn it logically or not I am not sure. I will check it with reference to the main input stage of the PSU, where this board has come from. Could the reference be associated with the input voltage auto-sensing? Or is this overly elaborate for that purpose? That unmarked flat part does appear to have some resistance, about 390ohms as measured in circuit, so probably the precision trimmed resistor you suggest. Regards Rob
Re: SM EVM A131-10 advice
On Sun, Dec 24, 2017 at 10:58 AM, Greg Smith via cctalk < cctalk@classiccmp.org> wrote: > Hi, I'm brand new to vintage computing and would love any advice. I'm > thinking of putting together a SM EVM A131-10 and would appreciate any > advice/knowledge on the unit. > Learn to read Russian? That's a Soviet-era computer correct? There are a few here that might be able to help. BIll
Re: Argh--my old faithful HP16C is failing!
Maybe this got missed. HP16C - PC software http://www.wrpn.emmet-gray.com/ Keven Miller - Original Message - From: "Curious Marc via cctech" To: ; Sent: Sat 23 Dec 2017 10:27 PM Subject: Re: Argh--my old faithful HP16C is failing! Thanks very much! I am going to install this one. But I was looking more specifically for a 16C on the PC. Anyone knows? Marc From: cctalk on behalf of "cctalk@classiccmp.org" Reply-To: "j...@cimmeri.com" , "cctalk@classiccmp.org" Date: Saturday, December 23, 2017 at 9:18 PM To: , "cctalk@classiccmp.org" Subject: Re: Argh--my old faithful HP16C is failing! On 12/24/2017 12:14 AM, Curious Marc via cctalk wrote: I did not find a good emulation on the PC. There is one that had a good demo but costs $20, and I was never able to buy it, their buying site has a bug. Marc http://hp15c.com/
Re: Help Identifying Components
On 2017-Dec-24, at 12:01 PM, Chuck Guzis via cctalk wrote: > On 12/24/2017 11:15 AM, Rob Jarratt wrote: > >> I think the orange components are capacitors (they are taller than the >> browner ones), but their markings don't seem to hint at the values, some are >> marked "AA4", which does not seem to correspond to any marking scheme I have >> been able to find. Any idea if they *are* capacitors and what the values >> might be? > > My guess is capacitors also. Noting they are paralleling resistors, they're probably just noise/AC bypass, on the order of 0.01 uF, and not overly consequential to understanding the basic circuit. Again, one can draw it out with the above presumption and then assess whether it makes sense or for alternative functions. > This "SMD Code Book" should be of some value: > > http://www.sphere.bc.ca/download/smd-codebook.pdf > > --Chuck
Re: Help Identifying Components
On 2017-Dec-24, at 10:27 AM, Rob Jarratt via cctalk wrote: > I am continuing work to reverse engineer the schematic for my H7826 PSU. I > have removed one of the daughter cards in order to draw its schematic, but I > can't identify some of the surface mount components on it. I have posted a > picture of it here: > https://rjarratt.files.wordpress.com/2017/12/50-19530.jpg > > The ones I can't identify are: > > 1. The component with two wide pins that looks like an IC > approximately in the middle of the board. It is marked M106 (or it might be > AA106) and 91813 underneath. I think it may be a resistor, but I am not > sure. > > 2. Just to the right of this is another much thinner two-pin component > which is black on top with a kind of white notch. I have no idea at all what > this is. > > 3. The three 3-pin black components to the left of the first > component. Two of them are marked "2T L" (or is that "ZT L"?), one appears > to be marked "2X I" (letter "ih", not letter "el"). I guess they are > transistors, but they may not be of course, and I don't know their pinout. > > > > Any help with identifying what these are would be very helpful. SMD codes are a mess as the same code is often used by different manufacturers for different devices. Resolving them is often an effort working between the multiple code possibilities, what makes electrical sense after reverse engineering the circuit topology, and ohmmeter measurements of the device. 2: Try measuring the resistance, if it's a low resistance perhaps a fuse as Chuck suggested, but considering the precision reference on the board, if it's a higher resistance perhaps a precision-trimmed resistor. 3: As per Chuck's suggestion likely bipolar transistors, and probably: 2T: PNP 2X: NPN with pinout (hopefully this renders unambiguously): C B E Try drawing it out presuming the above and then assess whether it makes sense electrically for polarity, current flow and control.
Re: Help Identifying Components
On 12/24/2017 11:15 AM, Rob Jarratt wrote: > I think the orange components are capacitors (they are taller than the > browner ones), but their markings don't seem to hint at the values, some are > marked "AA4", which does not seem to correspond to any marking scheme I have > been able to find. Any idea if they *are* capacitors and what the values > might be? My guess is capacitors also. This "SMD Code Book" should be of some value: http://www.sphere.bc.ca/download/smd-codebook.pdf --Chuck
RE: Help Identifying Components
> My guesses are as follows. > > 1. That "AA" or "M" looks to me like a Motorola logo. The fact that this > device > is polarized leads me to suspect that it's a diode. > > 2. I suspect that this thing is a fuse. > > 3. Almost certainly transistors. The center pin is usually the collector. > > --Chuck > Many thanks, those make sense. I tested the first one in circuit to see if it was a diode and that seems to be correct. I think the orange components are capacitors (they are taller than the browner ones), but their markings don't seem to hint at the values, some are marked "AA4", which does not seem to correspond to any marking scheme I have been able to find. Any idea if they *are* capacitors and what the values might be? Regards Rob
Re: Help Identifying Components
On 12/24/2017 10:27 AM, Rob Jarratt via cctalk wrote: > > 1. The component with two wide pins that looks like an IC > approximately in the middle of the board. It is marked M106 (or it might be > AA106) and 91813 underneath. I think it may be a resistor, but I am not > sure. > > 2. Just to the right of this is another much thinner two-pin component > which is black on top with a kind of white notch. I have no idea at all what > this is. > > 3. The three 3-pin black components to the left of the first > component. Two of them are marked "2T L" (or is that "ZT L"?), one appears > to be marked "2X I" (letter "ih", not letter "el"). I guess they are > transistors, but they may not be of course, and I don't know their pinout. My guesses are as follows. 1. That "AA" or "M" looks to me like a Motorola logo. The fact that this device is polarized leads me to suspect that it's a diode. 2. I suspect that this thing is a fuse. 3. Almost certainly transistors. The center pin is usually the collector. --Chuck
Help Identifying Components
I am continuing work to reverse engineer the schematic for my H7826 PSU. I have removed one of the daughter cards in order to draw its schematic, but I can't identify some of the surface mount components on it. I have posted a picture of it here: https://rjarratt.files.wordpress.com/2017/12/50-19530.jpg The ones I can't identify are: 1. The component with two wide pins that looks like an IC approximately in the middle of the board. It is marked M106 (or it might be AA106) and 91813 underneath. I think it may be a resistor, but I am not sure. 2. Just to the right of this is another much thinner two-pin component which is black on top with a kind of white notch. I have no idea at all what this is. 3. The three 3-pin black components to the left of the first component. Two of them are marked "2T L" (or is that "ZT L"?), one appears to be marked "2X I" (letter "ih", not letter "el"). I guess they are transistors, but they may not be of course, and I don't know their pinout. Any help with identifying what these are would be very helpful. Thanks Rob
SM EVM A131-10 advice
Hi, I'm brand new to vintage computing and would love any advice. I'm thinking of putting together a SM EVM A131-10 and would appreciate any advice/knowledge on the unit.
Re: Restoring a VT50 (VT52 actually) .
> From: Mattis Lind > Unfortunately I am not having any lutfisk this year. The rest of the > family is not very fond of it. I"m glad to see there are _some_ non-crazy people there! :-) Anway, I can way top that - the tradition Bermudian Christmas dish is cassava pie: make that wrong (starting with raw cassava root), and it will _kill_ you! :-) (Cassava root contains a cyanide precursor. That's what cassava root is banned for human consumption in Japan. Somewhat ironic, the land of 'fugu' banning it! :-) Noel
Re: Restoring a VT50 (VT52 actually) .
söndag 24 december 2017 skrev Chuck Guzis via cctalk : > On 12/23/2017 07:24 PM, Chris Elmquist wrote: > > > I’m not sure you can smell the difference between failed selenium > rectifiers and lutefisk... > > It probably doesn't get interesting until you toss in a can of > surströmming... > > --Chuck > > Unfortunately I am not having any lutfisk this year. The rest of the family is not very fond of it. I like it with white sause, mustard and green peas. In Sweden lutfisk is usually made from dried långa (ling?). Never had the pleassure of having a selenium rectifier fail so I can't compare. My personal view is that the smell of cooking lutfisk is not that bad. The rest of the family disagree.. Surströmming is a whole different matter in terms of smell. As far as I understand this is a summer thing. Nothing you have for christmas. One need some heat to make it ferment I guess. I have tested it once back when in university, in the summertime on a small island in the archipelego. The guy that oppened the can did so on the other end of the island. My remebrance was that it was ok with onion and potato in a bread. But there were plenty of alcohol involved so the memories are a bit fuzzy... /Mattis
