Panasonic FZ-1 Troubleshooting Guide

Panasonic's troubleshooting flowchart for the FZ-1 (service manual CPD9309012C0, p. 2-12)

Fault-finding on the Panasonic FZ-1 can follow Panasonic's own documents. The service manual has a one-page flowchart that sends each symptom to a group of parts, and the technical guide has detailed flowcharts for the power logic, memory, video, audio, CD-ROM drive and controller. The faults that owners meet most often today, failed capacitors and a stretched tray belt, come from the 3DO Development Repo and ConsoleMods and are added under the matching symptom.

Before you start

• Unplug the console before opening it. The POWER button switches the regulators through their control pins and does not break the mains, so the transformer primary is live whenever the plug is in.
• The CD-ROM drive has a class 1 laser. Panasonic warns against looking into the lens and against adjusting the preset resistor on the pickup. The laser diode can be destroyed by static: wear an anti-static wrist strap, put a conductive or steel sheet under the pickup, keep clothing away from it, and keep its flexible board shorted with the shorting pin or a clip while it is out of the drive.
• Panasonic's caution for disassembly is not to interchange screws between parts of the console. The order of disassembly is on the Panasonic FZ-1 General Maintenance page.
• Check which main board is fitted before using any part number or capacitor value. The three U.S. board types and their documents are listed on the Panasonic FZ-1 Capacitor Replacement Guide.

Panasonic's fault-finding order

Troubleshooting flowchart, service manual p. 2-12

Question	If the answer is the fault	Parts to check
Are +9 V and +5 V generated?	No	Power logic: IC11, IC31, F1, T1, D1, D2, SW51
Does the beeper sound?	Yes	Memory: VRAM IC300, IC302, IC320, IC322; DRAM IC310, IC311, IC330, IC331; connectors CN300, CN301, CN320, CN321
Does the TV show an abnormal screen?	Yes	CLIO and video: IC180, IC140, VRAM IC300, IC302, IC320, IC322, L180, CN500
Has the sound failed?	Yes	Sound: IC200, IC140, Q200, Q240, Q260, Q270
Has the CD-ROM drive failed?	Yes	Drive mechanism and drive board; interface: flat cables, IC120, IC600, Q630, CN620, CN630
Has the controller failed?	Yes	CN900, CN901, CN541, IC120, IC200

The technical guide notes that the console may beep at switch-on when it has a fault, so turn the television volume up before testing. The reference numbers are those of the first board type; check them against the parts list for your board.

No power

How the supply works

The transformer T1 delivers about 15 V AC (14.4 V measured on the community drawing) through the fuse F1 (3.15 A, 125 V) and the filter L1 to the bridge rectifier D1. The reservoir C1 (6800 µF, 25 V) holds about 14.5 V with the console on and about 18 V with it off. IC11, an SI-3090CA, makes +9 V; its pin 2 turns it on above 2.0 V and sits at about 2.6 V when running. IC31, an L4960, makes +5 V through the choke L31 and the filter capacitor C35; its soft-start pin 6 sits at about 5 V when running and is pulled to ground through R51 (1 kΩ) to switch it off. The POWER switch SW51 grounds both control pins when it is off. The community drawing gives the soft-start capacitor on pin 6 as C36 (10 µF) and the +9 V output capacitor as C631 (1000 µF).

Power section test values

Point	Value	Source
CN1, transformer secondary	10–18 V AC (Panasonic's acceptance range); 14.4 V measured	Technical guide 5-1-3; community drawing
C1	About 14.5 V on, about 18 V off; 15.7 V measured	Technical guide 3-3-1; community drawing
IC11 output (+9 V)	8.97 V measured	Community drawing
IC11 pin 2 (on/off)	About 2.6 V on (2.4 V measured); 0 V off	Technical guide 3-3-2; community drawing
IC31 output after L31 (+5 V)	5.00 V measured	Community drawing
IC31 pin 6 (soft start)	About 5 V on (4.86 V measured); 0 V off	Technical guide 3-3-3; community drawing
Fan connector CN660	8.96 V measured	Community drawing
T1 winding resistance	Primary 22 Ω, secondary 1.1 Ω	Community drawing

Over-voltage protection

Zener diodes D3, D12 and D33 watch the transformer output, the +9 V rail and the +5 V rail. If one of them conducts, the gate of the thyristor D2 rises to 0.5 V, D2 fires and the short across the supply blows F1. Panasonic gives the trip points as at least 34.0 V on the transformer secondary, 11.8 V on +9 V and 6.8 V on +5 V. A blown F1 is therefore often a symptom. The 3DO Development Repo adds that a laser current turned up too far can also blow the fuse.

Panasonic's power logic check

1. If both +9 V and +5 V are missing, check SW51. With the console on, its pins 2 and 3 are joined; with it off, pins 1 and 2. Replace SW51 if it does not switch.
2. If F1 has blown, fit a new 3.15 A fuse and switch on. If it blows again, watch the transformer output, +9 V and +5 V with a storage oscilloscope. Over-voltage on the transformer output means T1; on +9 V, IC11 or D11; on +5 V, IC31 or D32. If none rises, check D2 for a short between anode and cathode and replace it if shorted. If D2 is good, check C1, IC11 and IC31 and look for a short from the supply to ground.
3. If F1 is intact, measure 10–18 V AC on both terminals of CN1. If it is missing, replace T1. Then measure it across C3, after the filter L1; if it is missing there, L1 is open. If AC is present at C3 but the supply is still dead, replace D1.
4. If only +5 V is missing, check IC31 and its circuit. If the +5 V line is shorted, check D31, L31, the capacitors and the DRAMs and VRAMs on that line.
5. If only +9 V is missing, check IC11. If the +9 V line is shorted, check C12, the other capacitors on the line and the CD-ROM drive.

The 3DO Development Repo lists D11 as a common failure; on the community drawing it is the diode across the +9 V regulator IC11. It also reports that the FZ-1's regulators and diodes run very hot in normal use.

Capacitors in the power section

C35 and C36 are the capacitors most often found leaking on the FZ-1, and most FZ-1 faults are traced to them. Check the board and its traces around them after removing them. C1 is held down with glue that is easily mistaken for leaked electrolyte; C1 still ages and should be replaced. Values and part numbers are on the Panasonic FZ-1 Capacitor Replacement Guide; see also Capacitor Failure Symptoms.

Restarts and boot faults

Restarting in a loop before any picture

ConsoleMods traces this to C1 leaking onto C36. Replace both, check the nearby vias for blockage or corrosion and clean or bridge them, and check whether the electrolyte has reached the power switch.

Reset

Panasonic's fundamental check expects pin 152 (PON) of CLIO, IC140, to go from low to high after switch-on, and the reset signal to leave IC140 pin 50. If PON does not rise, check C401. C401 (22 µF, 16 V) sits on the back-up controller IC400. The 3DO Development Repo reports that C401 is missing from some FZ-1 boards from the factory; a missing or failed C401 stops the console detecting devices on the expansion port, which shows as long loading times with an XPort optical drive emulator. Fit a 22–100 µF capacitor rated 16 V or more.

Random resets, or a game that resets the console

Failing capacitors, a weak supply or faulty DRAM or VRAM can all reset a 3DO. The start-up memory test does not catch faults that only show while a game runs, and no modern replacement for the VRAM is known. Rule out the supply and the capacitors first.

Beep at switch-on

A beep sends Panasonic's flowchart to the memory section: the VRAMs, the DRAMs and, on the first board type, the two 50-pin connectors to the DRAM board. Check the supply and the clock and address lines of each chip; Panasonic's note is that no address or data line should sit stuck high, low or at a middle level.

Picture and sound

Picture and sound faults

Symptom	Probable cause	Action
Picture on one output but not the others	Cracked solder joint on an output socket, or a broken socket	Resolder or replace the socket
Poor RF picture on both channels	Dirty channel 3/4 switch	Work the switch back and forth
No picture on any output	Supply rails or capacitors; then CLIO (IC140), the encoder and VRAM	Measure +5 V and +9 V; follow Panasonic's video check
Rolling black-and-white picture	NTSC console on a PAL-only set, or the reverse	Use a television that accepts the console's standard
No sound	Audio DAC IC200, CLIO IC140, transistors Q200, Q240, Q260, Q270	Follow Panasonic's audio check

On the third board type (from serial number 4IKSI01001) the colour encoder is IC160 (DAVP536A-X1K), and Panasonic lists IC160 and the audio DAC IC200 among the major changes.

Disc tray

Tray faults

Symptom	Probable cause	Action
Tray will not open, opens slowly, or the motor runs and the tray slips	Stretched tray belt	Replace the belt
Tray will not stay open, or ejects as soon as it has closed	Stretched tray belt	Replace the belt
Tray does not move at all	No supply to the motor, or broken motor wires	Check the rails; check the thin motor wires; test the motor on a bench supply
Grinding, or the pickup does not travel	Damaged drive gear	Replace the gear

A printed replacement CD-ROM gear for the FZ-1 is published on Thingiverse.

Disc reading

• Check the disc first. Hold it up to a bright light; pinpoints or spots of light mean the metal layer is damaged and no polishing will recover it.
• Clean the lens. A fogged or scratched lens means a new pickup.
• Replace the capacitors. Failed power and RAM decoupling capacitors cause slow reading and stuttering video.
• Check the flat cables to CN620 and CN630 on the main board and the connectors on the drive board.
• The laser is the Sanyo SF-92.5. Much of the stock sold under that number has the wrong flexible cable arrangement, so a complete used drive (FZ-1, FZ-10 or the CR-563-B, CR-503-C and CR-503-K computer drives) can be the easier source.
• A new drive mechanism (Panasonic part LMXY0055) comes with a solder short and a lens cap fitted to protect the laser. Remove the solder and the cap after fitting it.
• Setting the laser current needs an oscilloscope. Turning the pot by trial and error can destroy the laser or blow the fuse. Panasonic's technical guide marks the test points on the underside of the CD-ROM drive board.
• A healthy FZ-1 can read CD-R, but CD-R is harder to read than a pressed disc. Burn at a slow speed on good media before suspecting the drive.

Games that will not run

The 3DO has no region lock, but some games need hardware or a video standard that a given console lacks. 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.

Controller

If the controller does not respond, check the controller port board connector CN900, its link CN901 to CN541 on the main board, and then MADAM (IC120) and the audio DAC IC200, which Panasonic lists in the controller path.

Related pages

• Panasonic FZ-1 R.E.A.L. 3DO
• Panasonic FZ-1 General Maintenance
• Panasonic FZ-1 Capacitor Replacement Guide
• Panasonic FZ-1 Documentation
• Panasonic FZ-10 Troubleshooting Guide
• Capacitor Failure Symptoms