Philips NMS 8245: The usual melted belt of the Floppy Drive.

Gallery:

Philips Videopac G7000 a little bit Dirty but Working. Nothing to write this time, just needed only a good clean up.

Gallery:

Dirty and Ruined Intellivision *Black Screen* repair.

It would not have been nice to put the intellivision in a very worn state and without a controller inside the spare parts box without even trying it :-)

Obviously the intellivision was not working, black screen.

The repair was simple, i have replaced the AM9114 (U8-B) RAM with a NEC 2114 and everything started working better than before :-)

I have also removed both labels in a pitiful conditions, now it looks better than before.

Gallery of the repair:

The restoration of the Sorcerer II of the Compudata (Exidy) was very simple, it was enough to replace all the tantalum capacitors with electrolytics one and make a good cleaning.

I tried the Sorcerer with the software downloadable at this link and to do a better understand the idea of the long loading (average 7 minutes) i have recorded the WAV file of the tape format on a Tape Cassette and used an old recorder to load the software, everything worked perfectly on the first try.

from Wikipedia;

The Sorcerer is a home computer system released in 1978 by the video game company Exidy.

It was comparatively advanced when released, especially when compared to the contemporary more commercially successful Commodore PET and TRS-80, but due to company focus on the coin operated video game marketplace resources were restricted for personal computer expansion and a separate division of the company was created.

Exidy Data Systems was headed by Paul Terrell to expand the product line to include small business computing with international distribution and technology license agreements to supplement corporate funding.

Distribution agreements with Dick Smith Electronics in Australia and Liveport in the UK as well as Compudata which included a manufacturing license to build, market and distribute the Tulip line of computers in Europe. Exidy sold the PC division to a Wall Street firm, Biotech, in 1983.

Gallery:

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Texas Instruments TI-99/4A Repair.

Defect:

• Garbage boot screen.

Replaced parts:

• 2 x TMS4116-15 RAM (U102 / U105)

Gallery of the repair:

This Amiga 4000 is completely devastated on both sides of the PCB by the leaked acid of the battery and kept in a humid room for at least 20 years.

There are still a couple of things to keep, but i will do it later if necessary.

First of all, a premise: All the repairs i do are for hobby purpose ONLY. It is NOT a job, and i fix stuff for a selected people group that i consider needs my help. All other people please ask somewhere else to get your items repaired back.

A guy contacted me asking help for a repair and after an exchange of messages i agreed to repair his Amiga 4000 which at boot only displayed a Black screen.

I immediately noticed a fairly important damage caused by battery and caps acid leakage.

After cleaned everything and replaced capacitors on motherboard / 3640 and PSU (the fault persisted, of course).

Next, i used the Chucky DIAGROM: the DIAGROM is useful to understand what might be that doesn’t work, and the output via RS232 is also very useful if nothing is displayed on the screen.

Unfortunately the DIAGROM worked partially because the mouse was completely dead and therefore i have used the output via Serial but this is also worked partially because evidently also the serial is dead but in some precarious moments i  have tried to run the Sound test and no sound was reproduced.

Moral: Partially working Serial port + Mouse not working + Audio not working = Paula.

Replaced the PAULA (U400) everything started to work correctly apart the FASTRAM with 4 x 4MB SIMM modules each the system sees only 2 in the U852/U853 positions for a total of 8MB.

The problem was a short circuit probably caused by the acid leaking from the battery, i had to clean the PCB for the tenth time and the problem was fixed.

No more other to say, except that i am happy i succeeded to repaired this Amiga 4000 for a person that needed my help.

Gallery of the repair:

12►

Video:

Texas Instruments TI-99/4A Repair (1 of 6)

Defect:

• Black Screen and deafening sound in background.

Replaced parts:

• 1 x TMS 4732/2532 ROM (U610)

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 Texas Instruments TI-99/4A Repair (2 of 6)

Defect:

• Black Screen and deafening sound in background.

Replaced parts:

• 1 x MCM 6810P (128 x 8-Bit Random-Access Memory TTL/DTL) (U608)

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Texas Instruments TI-99/4A Repair (3 of 6)

Defect:

• Black Screen and deafening sound in background.

Replaced parts:

• 1 x 74LS138 (U504)
• 1 x 74LS138 (U505)

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Texas Instruments TI-99/4A Repair (4 of 6)

Defect:

• Black Screen and deafening sound in background.

Replaced parts:

• 1 x TMS 9900NL CPU (U600)

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Texas Instruments TI-99/4A Repair (5 of 6)

Defect:

• Garbage Boot Screen.

Replaced parts:

• 1 x TMS4116-15 RAM (U106)

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Texas Instruments TI-99/4A Repair (6 of 6)

Defect:

• Various problems with audio playback.

Replaced parts:

• 1 x SN76494N – Digital Complex Sound Generator (U511)

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