zinok

Hi John, thanks for the welcome message, I can see there is nice people here like you said. I already downloaded the manual you mentioned but it's not the one for repairing the 5200. CPUWIZ, couldn't find any info about that part either, anyway I added it to the compatible list. I couldn´t find those memory parts in some electronic shops I called, but I found some 256Kx1 DRAMs in a 286 MOBO, so I replace the fused drams with this ones grounding their not used address inputs (pins 1,9 not used in 16Kx1 drams). The replacement parts are TMM41256CP-10, featuring 100ns RAS access time, 50ns for CAS, and 100-220ns for cycle times (100 for page mode). I suppose it should work with this ones. Anyway, now there is no heat on memories but the screen stills black for every game except Defender, where shows up on the rigth of the screen a vertical white line. On power on some random inverted horizontal lines appears over the vertical one, but after a little while this jumping random lines tends to be less and finaly they vanish leaving only the vertical white one on the screen. If anyone has an open unit and feels like testing some VDC values, I measure this (those in parenthesis are from the schematics for the four ports in this site) Q1: 4.02 V (4.3) - 3.45 (3.5) - 1.42 (1.2) Q2: 4.02 V (4.3) - 3.44 (3.5) - 0.92 (1) Q7 (emisor): 9.4 (14) This last one is quite far from the value in the schematics. For the three test points over U8 on the board (left to right): 3.93 - 4.92 - 0.36 From the regulators inside the unit: 9.3 and 4.94 V (side pins) I'm using a regulated power supply at 11.5 V - 10.6 V when 5200 powered on (it can handle three amps). Now I'm really stuck, any clues? Should I post this in the hardware forum? Thanks, Zinok

Hi, I am a newbie trying to fix my 2 ports 5200, I've already replace a resistor and the power on section flip flop IC. Now it turns on but I get a black screen. Finally I realized that two dram chips gets too hot, I swap them with adjacent ones and they still getting hot in their new positions, so I suppose I've got to replace this two with new ones (right?). The ram chips on my board are MCM4517P15. I couldn´t find the datasheet of this IC because it is discontinued, does anyone knows of a replacement for this IC, all I know is that it´s a 16Kx1 dram. What are the access, cicle times of it? BTW, Is there some place on the net to download the service manual for the 5200? Thanks, Zinok

Ok guys, thanks a lot, I got borrowed a cammera to leave no doubts about this, but now the data is for sure rigth. Anyway, here is the picture. Thank you very much for the help

Hello Micth, I´m confused, I´ve seen the power section schematics and thought it was the 56 ohm one, but on the same schematics I haven´t found the 560 ohm one that it´s in serie with the missing one on my board, so I thought that maybe the schematics was wrong. Did you get the value from the schematics? Of course I´m not very experienced so I must be wrong, but I want to be sure to put there the right one. Thanks

Hi, I have a missing resitor on my two ports 5200 board, is the one identified as R53 printed on the pcb. ---------------------------------------------------------- Back of console [MODULATOR] R53 R61 C50 R62 ! ! ! ! ! +------+ ? ! ! ON/ ! / R59 ? / === / ! OFF ! ? ! !SWITCH! ! ! ! ! ! +------+ Front of console ---------------------------------------------------------- (Let me know if the ascii picture doesn´t look fine, I shoud do this on a graphic program) Could anyone please tell me the value of it. Maybe that´s all it needs to get back to life. The resistor is missing because I took it away long time ago when it got burned. It would be great to play Star Raiders and some other games again on the real thing. Thanks, Zinok.