Could anyone identify this component please? - Page 1
Forum section: electronics / repair

author: docca
author_rank: Newbie
timestamp: July 22, 2023, 03:00:33 am
content: So, I mistakenly connected a 4-pin Molex connector backwards on a ATAPI DVD-ROM drive (yes, ATAPI IDE, it's ancient equipment, long story) and it apparently fried something on the drive's PCB. Basically, applied 12V to a 5V rail.I was connecting it to a cheap IDE to USB adapter, and due to the poor molding of the external power supply connector, the keyed corners are mostly non-existant...Anyway, I checked for shorted caps and blown components to no avail. After correctly connecting to a proper power supply, I noticed a very hot chip with the thermal camera, which probably took the blow as it's connected directly to the 5V rail:The markings are way too generic and I don't recognize the manufacturer's logo. Does anyone know what this component could be? My best guess so far is an op-amp, but which one?The hot component reads: 613 478A, and there is 5V on pin 3. The component below appears to be almost the same, and reads 613 592B.

author: fzabkar
author_rank: Super Contributor
timestamp: July 22, 2023, 03:17:14 am
content: The logo belongs to Microchip.2006 Product LineUp:https://web.archive.org/web/20061016034101/http://www.microchip.com/stellent/idcplg?IdcService=SS_GET_PAGE&nodeId=69FWIW, TI makes an 8-pin TL592B ...

author: docca
author_rank: Newbie
timestamp: July 22, 2023, 04:17:23 pm
content: Thanks for the info! However looking at the datasheet section, I cannot find anything resembling "631". The closest I found was 619, then 6231.I did found this datasheet by chance from Rohm Semiconductor:https://pdf1.alldatasheet.net/datasheet-pdf/view/916152/ROHM/RB061US-30.htmlIt *does have* "613" printed on the chip and it's a Schottky barrier diode. Would that make sense for both chips? So that would make the lower line just date codes...

author: fzabkar
author_rank: Super Contributor
timestamp: July 22, 2023, 04:35:41 pm
content: ROHM RB061US-30 doesn't make sense to me. Could we see a photo of the whole PCB?

author: docca
author_rank: Newbie
timestamp: July 22, 2023, 04:53:40 pm
content: Here you go. This a controller for a Toshiba SD-M1802 DVD-ROM drive (IDE), Please note that I took out the "offending" component in this photo, it was soldered right beside the other 613 chip.

author: fzabkar
author_rank: Super Contributor
timestamp: July 22, 2023, 05:06:46 pm
content: "613" must be a date code.Firstly, it would be unusual for two identical chips to have different date codes, as they would more than likely come from the same batch.Secondly, the date codes of the other chips are 0610 (MCU), 0614 (flash), and 0619 (RAM).All the main chips appear to be powered from +5V, so one would have to wonder whether they survived. I would check whether the Vcc pins of each chip are directly connected to the +5V Molex pin.https://tvsat.com.pl/PDF/E/en29f002a_eon.pdf(EN29F002AT)https://pdf.dzsc.com/M11/M11B416256A-25J.pdf(M11B416256A)https://pdf.datasheetcatalog.com/datasheet2/8/0i07kdfq0lf2yqqei5wh1z35g5fy.pdf(M63028FP)It might help to see the other side of the PCB.Is either of IC4 or IC5 connected to +12V? If so, then they may be power supply supervisors. There is a "PRST#" near IC4 which would tend to confirm this.

author: docca
author_rank: Newbie
timestamp: July 22, 2023, 05:57:21 pm
content: Thanks for the datasheets. I checked the VCC pins for the two DRAMs and the Renesas chip and they show around 1.3-1.4 ohm from the +5V pin on the Molex connector. I guess that would mean they're not directly connected?Here is the back of the board.No, IC4 and IC5 do not seem to be connected to the +12V pin. They both are connected to the +5V though.

author: fzabkar
author_rank: Super Contributor
timestamp: July 22, 2023, 06:22:19 pm
content: L401 is a low pass filter in series with the +5V supply. I expect that the resistance between its outer pins would account for your measurements. Therefore, I would think that the chips are essentially directly connected to the Molex. :-(Can you determine where the PRST# test point goes? Is it generated by IC4, and is there a pullup resistor between this point and +5V?

author: DrOnline
author_rank: Newbie
timestamp: July 25, 2023, 06:29:50 am
content: Hi, I can't help you identify the component, but are you sure it says 613, and not 6l3 (letter L)? Looks like it to me. Might help your search, if you agree.

author: wraper
author_rank: Unknown
timestamp: July 25, 2023, 06:42:44 am
content: I fail to recall which manufacturer it was exactly, but if "M" is not within circle, it's not microchip. There was one very similarly looking except lack of circle.

author: wraper
author_rank: Unknown
timestamp: July 25, 2023, 07:22:14 am
content: Finally remembered, it's Mitsumi.

author: Greybeard
author_rank: Frequent Contributor
timestamp: July 25, 2023, 07:50:42 am
content: How could that happen?Normally Floppy/CD/DVD drives use 4-pin AMP (not MOLEX) power connectors which are polarity coded by the shape of the connectors frame.

author: Nusa
author_rank: Super Contributor
timestamp: July 25, 2023, 09:55:59 am
content: Quote from: Greybeard on July 25, 2023, 07:50:42 amYou took the wrong lesson from the picture. The parts shown are identified, but it did not say were the sole source of 4 pin hard drive connectors. AMP did make them first and people sometimes incorrectly called them Molex. However, the completely compatible Molex 8981 series has also been made for the last 40 years, so a lot of them really are Molex. There are probably other manufacturers as well.

author: docca
author_rank: Newbie
timestamp: July 25, 2023, 02:16:20 pm
content: I'll check it later today, but I think it should have a pullup resistor.

author: docca
author_rank: Newbie
timestamp: July 25, 2023, 02:18:14 pm
content: You're correct, that should be referred to as AMP.But anyway, it was a cheap external power supply that had a badly molded AMP-like connector, so the flat parts are actually almost rounded. So, in it went and... zap!

author: docca
author_rank: Newbie
timestamp: July 25, 2023, 02:21:56 pm
content: But wouldn't that be a little ambiguous? I'd like to think that the manufacturers must have rules for avoiding ambiguous markings, wouldn't they? I'll search for it anyway, thanks!

author: tooki
author_rank: Super Contributor
timestamp: July 25, 2023, 03:03:20 pm
content: Quote from: docca on July 25, 2023, 02:21:56 pmRules for avoiding ambiguous markings?!? Oh, if only...Please quote the messages you're responding to (click Quote instead of Reply), since otherwise we have no way of knowing which reply corresponds to which message you're replying to!

author: fzabkar
author_rank: Super Contributor
timestamp: July 25, 2023, 04:40:30 pm
content: Sorry for the misdirection.Try this:https://web.archive.org/web/20061212071124/http://www.mitsumi.co.jp/Catalog/indexuse/index_e.htmlFWIW, Mitsumi does have a reset IC (plus 3.4V regulator - for the SoC?) that fits the part marking, but it has the wrong package:https://web.archive.org/web/20071028215831/http://www.mitsumi.co.jp/Catalog/pdf/regulate_mm_1478_e.pdfhttps://www.semiee.com/file/EOL/Mitsumi%20Electric-MM1478A.pdfhttps://pdf1.alldatasheet.com/datasheet-pdf/view/97400/MITSUMI/MM1478.htmlThere is also a MM1592B 2.1V regulator IC (which doesn't seem to fit the application, unless this rail is required by the SoC):https://web.archive.org/web/20070709223858/http://www.mitsumi.co.jp/Catalog/pdf/regulate_mm_159x_e.pdfhttps://pdf1.alldatasheet.com/datasheet-pdf/view/153642/MITSUMI/MM1592A.htmlThe second line does appear to reflect the part number:https://nmbtc.com/product-category/charge-control/Edit:These chips do seem to come in an SOP8 package:https://www.aliexpress.com/item/1005004010250474.html(MM1592FFBEG)https://ae01.alicdn.com/kf/S891c67b5a6954c6793083302593416048/2PCS-MM1592FFBEG-MM1592FF-SOP8-Brand-new-original-IC-chip.jpg

author: docca
author_rank: Newbie
timestamp: July 26, 2023, 12:33:18 am
content: Quote from: fzabkar on July 25, 2023, 04:40:30 pmOh wow, thanks for the thorough research!

author: DavidAlfa
author_rank: Super Contributor
timestamp: July 26, 2023, 03:16:45 am
content: Here you have the schematics for the SD-M1502, which has a suspicously similar IC (IC0001), looks like another Mitsumi chip, MM1456 orM1458(Another reset IC + regulator).https://fccid.io/CJ6AT00-046/Schematics/Schematic-Diagram-ExhibitG-116069.pdfHowever it's a 7-pin part, combining what would be pins 6&7 into just pin 6.Indeed, the MM1478 seems to match very closely!

author: Swake
author_rank: Frequent Contributor
timestamp: July 26, 2023, 06:40:28 am
content: Spectacular deep collaboration search! Thanks for the read, it is very entertaining.