Ebay PCB - no schematics to be found - Page 1
Forum section: electronics / projects

author: Matthew98
author_rank: Regular Contributor
timestamp: March 24, 2018, 04:36:34 pm
content: Hey guys, I bought this PCB from ebay :https://www.ebay.com/itm/TDA7293-Amplifier-Amp-Bare-PCB-Board-For-DIY/401107653520?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m2749.l2649To found, that there is no scheme, information or picture on the whole web about it... :/ Can you guys help me ? Maybe Im missing some Chineese website or something...If there is no other option, I will try to guess the components from the datacheet, as I suspect Chineese to not go far from it...

author: cstratton
author_rank: Regular Contributor
timestamp: March 24, 2018, 04:44:30 pm
content: While that should be fairly trivial to figure out from the data sheet (probably it is little more than the reference design), what is your goal?Buying someone's factory scrap (potentially with design errors... think why they'd be selling them) doesn't make a lot of sense. Likely sourcing the parts in ones and two is going to cost far more than an assembled board.If you want an amp, buy an ampIf you want a kit, buy a kitIf you want an original project, get the data sheet, a pot of coffee, and fire up kicad or whatever you prefer

author: Matthew98
author_rank: Regular Contributor
timestamp: March 24, 2018, 04:55:08 pm
content: Because I have a "shitload" of components including the two TDA´s 7293s Along with some Sony´s speakers and would like to scrap together a decent sounding Hi-fi system for cheap and fast.And BTW. They are selling them, because they are out there.... If they will have something to sell, they will sell it.. Its easy.I dont have the time neither the knowlage to make my own design. I will be glad if I make this design work on my own.Thats why I bought it, and thats why im posting it there...

author: ebastler
author_rank: Super Contributor
timestamp: March 24, 2018, 05:19:25 pm
content: No schematics, but at least a parts list. (I assume the seller didn't include that with your PCB either?)No warranties; this is just a random Google hit:http://manualzz.com/doc/41953638/tda7293-amp-kit-installation-instruction-below-is-oclhttp://bricolages-electroniques.e-monsite.com/medias/files/tda7293-amp-kit-installation-instruction.pdfEDIT: Direct PDF link added (both links have the same info)

author: Matthew98
author_rank: Regular Contributor
timestamp: March 24, 2018, 05:41:04 pm
content: Thanks !No, there was just the PCB in the box and go figure...That should be planty help to me.How did I not find this ?!

author: ebastler
author_rank: Super Contributor
timestamp: March 24, 2018, 07:19:55 pm
content: Quote from: Matthew98 on March 24, 2018, 05:41:04 pmToo much background noise from ebay and aliexpress sellers in the search results...Here's a thread where someone has reverse-engineered the schematics of the "XY Hifi" TDA7293 amplifier. I have not checked whether it is the right PCB however, and can't vouch for the quality of the schematic either. That forum lets only registered users see the attachments, I did not want to register just for that.http://www.diyaudio.com/forums/chip-amps/266996-tda7293-power-amp-2.htmlGood luck with your build! Don't forget a decent heat sink.

author: WhichEnt2
author_rank: Regular Contributor
timestamp: March 24, 2018, 07:41:38 pm
content: Do you asked the seller about schematic yet?

author: ebastler
author_rank: Super Contributor
timestamp: March 24, 2018, 07:51:40 pm
content: Quote from: WhichEnt2 on March 24, 2018, 07:41:38 pmIf you read the posts in various forums and the offers on ebay etc., the sellers' policy seems to be: (a) There is no schematic at all, and (b) information about component values and how to populate the board is only provided if you order a full kit. I assume the kits will typically come with the single page I linked to above.

author: WhichEnt2
author_rank: Regular Contributor
timestamp: March 25, 2018, 01:10:18 pm
content: I don't.But I always requested docs if necessary and for a few attempts - about 1/2 is positive for pcbs.Once I bought a trafo for dedicated project and obtained docs on that project through seller, pretended that "I want to buy" pcb from them.

author: moffy
author_rank: Super Contributor
timestamp: March 26, 2018, 12:00:37 am
content: I did my own drawing for the PCB. Hope it helps. I might have added a component or 2, can't remember.

author: Matthew98
author_rank: Regular Contributor
timestamp: March 28, 2018, 09:42:48 pm
content: Just to sum up, the seller responded, that he could not find any documentation, I built the circuit according to instructions above and i will be testing it out soon. I expect it to blow up, as I had to improvise a bit... a lot of times...*Had to order few components from ebay, as mine were for too low voltage and I didnt want to risk it blowing up and taking the IC along.So It will take some time.