Goldstar GDO-101M Troubleshooting Guide

Rear of a GDO-101M

Fault-finding on the Goldstar GDO-101M and the Korean GDO-101 starts from GoldStar's owner's manual, which has a short list of user faults. No GoldStar service manual has been found. The board-level checks below use a community drawing of the 6870S-263AA power supply, Console5's capacitor list and repair reports from the 3DO Development Repo, ConsoleMods and owners' forum threads.

Before you start

• Unplug the console before opening it. The mains goes straight to the transformer and the POWER switch only turns off the regulators, so the transformer primary is live whenever the plug is in.
• The GDO-101M is an NTSC console. A PAL disc made for European systems may not run on it, and a PAL-only television may not show its picture.
• Check the cables and the internal connectors first. A broken wire or a plug left out after earlier work causes many of the symptoms below.

GoldStar's own fault list

User faults in the GDO-101M owner's manual (pp. 22–23)

Symptom	GoldStar's cause	GoldStar's remedy
The tray pulls in and pops straight back out	Disc not seated, so the tray cannot retract	Reseat the disc and close the tray again
The disc spins for a few moments, then the tray comes out again	Disc unreadable: dirty, scratched, warped, upside down, or an incompatible or PAL format	Wipe the disc from the centre outwards; check it lies flat and has a compatible logo
The game freezes and does not respond	Software	Wait a couple of minutes, then restart by opening and closing the tray
The game restarts from the beginning	The laser lost its place on the disc; the console is sensitive to knocks	Stand the console on a stable surface, away from vibrating speakers
The console says it cannot save	Save memory full	Delete items with a storage manager disc, or add a storage peripheral
The controller does not respond	Lead pulled out of the control port; some titles ignore pads after the first	Reconnect the pad

When these do not explain the fault, work through the sections below.

No power

Work along the supply with a meter, using the values on the community drawing of the 6870S-263AA board:

1. Measure the transformer secondary at CON1 on the power board: about 16 V AC (15.8 V on the drawing). If it is missing, check the transformer and the mains lead.
2. Measure across the reservoir C3 (4700 µF): about 18 V DC. If it is missing with AC present, check the fuse F1 (3.15 A), the filter LF1 and the bridge DB1 (RBA402).
3. Measure CON3 pins 5 and 6: 5.05 V. If C3 is good and this is missing, the fault is in the L4960 stage (IC2 with L1, D1, C9 and the soft-start capacitor C10) or in the POWER switch circuit. The switch node reads 4.93 V with the console on.
4. Measure CON3 pins 3 and 4: 11.88 V, from the PQ12RF2 (IC1) and its output capacitor C4.

The 3DO Development Repo notes that a fuse rarely fails on its own, and that turning a laser's current up too far can blow it; find the cause before fitting a new fuse. The capacitor positions are on the Goldstar GDO-101M Capacitor Replacement Guide. Where the original supply cannot be saved, a PicoPSU-based replacement is sold for this model.

Boot faults

Logo, then a black screen in a loop

The console shows the 3DO logo, then a black screen, and keeps repeating. ConsoleMods traces this to the drive: the microswitches on the drive assembly and the flexible cable between the drive's two boards. The cable flexes each time the sled moves and its conductors crack; replace it with a 30-way, 1 mm pitch, 200 mm cable with the contacts on the same side at both ends, longer than the original. The first production run of GDO-101 consoles had a faulty cable that GoldStar replaced under warranty.

Will not start from cold

On a GDO-101M that fails to start from cold, ConsoleMods suggests replacing C123, next to the coin cell, with a 22–100 µF capacitor rated 16 V or more. Console5's list for the 6870S-260AA main board has no C123, so check whether the position is fitted on your board before ordering.

Random resets, or some games reset the console

Bad capacitors, a weak power supply, or failing DRAM or VRAM can all reset a 3DO. The console's start-up memory test does not catch faults that show only while a game runs, and there is no modern replacement for the VRAM. Rule out the capacitors and the supply before suspecting the memory.

Disc tray

Tray faults

Symptom	Probable cause	Action
Tray opens at switch-on, or closes fully and then opens again	The tray-closed actuator does not reach its metal tab, so the console never sees the tray as closed	Bend the tab forward very slightly with pliers so the actuator is fully pressed; check the close-detect switch
Tray does not stay open, or closes before the disc is placed	Open-detect switch	Clean or replace the microswitch
Tray slow or stuck part way	Tabs broken off the shaft in the tray gear train	Fit a new shaft (printable replacement available)
Tray does not move at all	Limit switches, broken motor wires, or no motor supply	Check the switches and the thin motor wires; test the motor on a bench supply

Disc reading

Reading faults

Symptom	Probable cause	Action
Grinding from the drive; disc never spins	Composite gear between the sled worm and its motor destroyed	Replace the gear, or fit an optical drive emulator
Laser runs into the spindle; no disc detected	Sled home microswitch	Clean or replace the microswitch
New laser moves but the disc does not spin	Anti-static solder bridge still on the new SF-C93AQ	Remove the bridge with solder wick
Pressed discs read slowly or full-motion video stutters	Dirty, fogged or weak laser; capacitors; a damaged disc	Clean the lens; recap; check the disc against a light for pinholes in the metal layer
Burned CD-R will not read	Weak laser, or a disc burned too fast or degraded	Burn at a slow speed on good media; a healthy GDO-101M reads CD-R

The replacement laser is the 10-pin Sanyo SF-C93AQ, as used in the Sega CDX. To change it, unplug the 4-pin, 2-pin and flexible connections, and take out only the guide rail nearest the sled motor; the other side of the laser block is open and slides off its rail. The laser's current can be adjusted with the pot on the pickup, but the correct setting needs an oscilloscope, and turning it up by trial and error can destroy the laser or blow the fuse.

Video

• Try each output in turn: RF, composite and S-Video. If one works and the others do not, look for cracked solder joints on the output sockets.
• If the RF picture is poor on both channels, work the channel switch back and forth to clean it.
• No picture on any output: check the supply rails and the capacitors before suspecting the video chips.

Games that will not run

Some games need hardware that the GDO-101M does not have. Japanese games that use the kanji ROM fitted only to Japanese consoles fail on other models, and some games run only on PAL or only on NTSC consoles without saying so. The 3DO itself has no region lock; these failures come from the games' own requirements.

Optical drive emulators

• Console resets after the splash screen with an XPort fitted: on one GDO-101 the expansion port connector had pins that were never soldered. Resolder the connector.
• Console does not start with an XPort connected: the supply may not deliver enough current, or the connector is dirty.
• Long loading times with an XPort: on the FZ-1 the cure is a 22–100 µF 16 V capacitor on the expansion port reset line (C401), and the 3DO Development Repo reports the same fault on the GDO-101.

GDO-101 (Korea)

The Korean GDO-101 is rated for 220 V, 60 Hz only, and its plate says so. Check the plate and the supply it has been run from before diagnosing anything else; archive3do advises a converter, or fitting the supply from a North American console. The drive and board faults above apply to it, since the Korean consoles share the hardware revisions of their export counterparts.

Related pages

• Goldstar GDO-101M 3DO
• Goldstar GDO-101M General Maintenance
• Goldstar GDO-101M Capacitor Replacement Guide
• Goldstar GDO-101M Documentation
• Capacitor Failure Symptoms