Turbo Duo

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Chips & ICs

Leaking Capacitors

Turbo Duo consoles suffer from surface mount capacitors that leak. Problems related to defective caps tend to first appear as poor-quality audio. If left unchecked, damage to surrounding components and traces may result. Beware of any machine sold as working but has not had it's capacitors replaced. If you own an unserviced Duo, consider this process a necessity.

Capacitor List

Turbo Duo Console

Purchase these parts as a kit

Turbo Duo capacitor map
C101	100uF	6v
C102	3.3uF	50v
C105	22uF	6v
C110	22uF	6v
C122	100uF	6v
C133	22uF	6v
C135	47uF	16v
C136	100uF	16v
C149	47uF	16v
C159	22uF	6v
C163	100uF	16v
C164	22uF	6v
C165	22uF	6v
C200	22uF	6v
C201	100uF	6v
C202	100uF	6v
C301	1000uF	16v
C305	330uF	16v
C306	220uF	16v
C307	470uF	16v
C308	470uF	16v
C310	330uF	16v
C311	100uF	6v
C312	330uF	16v
C322	22uF	16v
C323	22uF	16v
C325	100uF	10v
C501	100uF	6v
C507	100uF	6v
C512	22uF	6v
C515	22uF	6v
C517	22uF	6v
C519	22uF	6v
C521	22uF	6v
C523	22uF	6v
C525	22uF	6v
C526	22uF	6v
C604	10uF	16v
C610	10uF	16v
C612	47uF	6v
C613	10uF	16v
C614	10uF	16v
C615	47uF	16v
C616	22uF	16v
C631	100uF	6v
C653	10uF	16v
C670	4.7uF	16v
C671	4.7uF	16v
C674	4.7uF	16v
C675	4.7uF	16v
C678	100uF	6v
C679	100uF	6v
C884	22uF	16v
C961	10uF	16v
C962	470uF	16v

Power Supply HES-ACA-05

A/C Adapter Supply filter capacitor is available here

HES-ACA-05 Power Supply
10,000uF	16v

Jailbar Fix

See Hu6260 for JB fix locations

Schematics (partial)

Partial schematics for some circuits are available on the TurboGrafx_16 page. Not everything will be the same, but many ICs and supporting components are similar.

Bench Testing the CD Drive

Removing the CD hub

In order to test the CD mechanism while the case is apart, you'll need to remove the magnetic CD hub from the upper case half. The pic on the right shows the process.

CD Adjustments

  • Adjustment pots:
    • VR101 (20K): E/F Balance
    • VR102 (10K): Focus Bias
    • VR103 (20K): Tracking Gain
    • VR104 (20K): Focus Gain (CXA1081M, pin 19)
    • VR105 (500): VCO (PLL)

Replacement for broken pots are available in the store: VR101, VR103, VR104, VR102 VR105

CD Test Points

If you follow the datasheets for the Sony chips, some of these test points make sense and some don't. These were traced out over the course of a very long evening, using service manuals from other CXA1081/CXA1082/CXD1167-based CD players as a guide, so I apologize if there are any errors or ambiguities. P5 is the most useful connector and with a scope & a sharp ear you should be able to dial everything in just fine.

  • Test points, connector P5:
    • Pin 1: Laser diode power (?)
    • Pin 2: RF
    • Pin 3: Tracking Error (CXA1081M, pin 20)
    • Pin 4: /LD ON (Disc in) (CXA1081M, pin 29)
    • Pin 5: ASY
    • Pin 6: Ground

  • Test points, connector P6:
    • Pin 1: PLCK (pin 70, CXD1167)
    • Pin 2: GND

  • Test points, connector P7:
    • Pin 1: ??
    • Pin 2: D78C14GF pin 37
    • Pin 3: Top of VR103
    • Pin 4: Focus Error (Pin 48, CXA1082)
    • Pin 5: Focus Error -
    • Pin 6: TA -
    • Pin 7: VC / SL+

Setting VCO: You shouldn't have to touch VCO, but if someone has gone wild making random adjustments, it will probably be necessary.

  1. Disconnect power
  2. Place frequency counter on PLCK at connector P6, pin 1
  3. Connect ASY (connector P5, pin 5) to ground
  4. Connect power
  5. Set VR105 for a reading of 4.3218Mhz

I don't have a published spec, but a reading of ~4.3 - 4.4Mhz seems to work across a variety of test discs. 4.3218Mhz is the standard frequency for VCO. My preferred test is to use a clean-disc game with FMV, like It Came from the Desert. If long videos briefly glitch out but otherwise the drive seems fine & the disc is clean, it may be due to an incorrectly set VCO. I've had better luck with VCO set a little too high rather than a little too low.

Controller Schematics

Controller schematics, drawn by Ciccio Petito, with local addition of DIN 8 pinout for US TG16