Recent content by hbsoftware

Today i tried to replace the cylindrical crystal. I think its related to the cmos timer. Reason for that is that i connect my frequency counter to the crystal pins and i get 50hz, same with my multimeter on frequency mode...i think it should be around 32khz. The crystal is connected to this...

Hi . I did the work on the living room were there is no earth wire..only on the kitchen and bathroom and on my office...i should have used my isolation transformer to power the soldering iron but was lazy.....i verified for shorts, verified the edge connector pins, ram, tried with and without...

Hi, i made sure the polarity was correct. The pc had a button cell too but soldered to the board..i took note before removing it

Hi friends I was offered this all in one compaq for free...it was working fine for a couple of days until i decided to replace the dead bios battery. I soldered a socket for a cr2032, then i brushed off the dust with a toothbrush...thats all i did. Now it wont post ..nothing... putting a bios...

Hi i recently accquired this rare computer on local facebook marketplece. At first i didnt know what it was.... from the pictures it looked like a dumb terminal, but the fact it had twin floppy drives made think it was a computer... the possibility of having a green or amber monitor plus the...

hi here is a picture of the board and in the second picture i believe the chip saying "Flash" is the bios but i cant tell what brand it is... it appears to have sticker residue so i believe it had a sticker some time ago the number on the chip is n28f010 but that tells nothing searching online i...

HI For eliminating any external sources of problems i am testing the bare board only and with a good known psu it stopped working under any condition now

hi everyone i am having a problem with a socket 5 mainboard ( the first gen pentiums with the fdiv bug) i got the system at a junkyard, no cpu or ram, it is a compaq deskpro machine fitted a cpu, populated the ram, it worked and i was trying to get it to boot from a hard drive, then it stopped...

if in doubt i would use a current regulated bench supply to supply 5v to the 5v rail ...slowly raise the current and if nothing explodes or gets hot or starts current limiting by dropping the voltage then its good to go.... but maybe not worth it since the 14 ohms is the same reading as a good...

I find that opening the hard disk and very very gently twisting(rotating) the read write head with tweezers is the best method, if the frezzer doesnt work of course. the head support is springy and will accept some torsion and get back to position but you must be very gentle and carefull with...

And maybe a bit offtopic but maybe someone finds interesting, here are some pics of my workspace, the reason i dont have a lot of resources and tools for diagnosing pcs is beacuse i "work" mostly with old vacuum tube stuff mostly tvs, but i also have a passion for vintage pcs and especially for...

Hi modem7 thank you for the reply. i also found that symptom very unusual and couldnt find anyone reporting the same problem..... About the AT keyboard it was a btc 5349 so after some research i suspect it is an auto sensing keyboard and that explains why it also "worked" One thing i also...

ok so after fighting this issue for quite some time , dessoldering some 74LS ics to look for broken traces underneath i found out that the problem was software related:ROFLMAO: i managed to write a dos 360k boot disk and after booting from it, the keyboard worked strange because i booted the nec...

Hi everyone i recently accquired a nice turbo xt clone with a NEC D5126 20mb mfm drive the computer boots fine after cleaning the mainboard , reseating all the ics and deoxit the sockets the hard disk works and sounds healthy and i tested it completely on other pc too but i am having a problem...

greetings to all first of all let me tell you English is not my native language so sorry for any errors that my text may contain. I recently purchased an Amstrad PC1512 wich i want to restore and it came with a 20mb MFM Tandon drive , model TM262, its is a rebadged western digital i think the...