- Voltage Regulation: Zener-based, adjustable simple series regulator
- IC100: JRC 2073
- IC700: HuC6280
- IC701: HuC6270
- IC702: HuC6260
- IC703: HSRM2264LM10
- IC704: HSRM20256LM12
- IC705: HSRM20256LM12
- IC800: BU5782K
Turbo Express / PC-Engine GT handhelds have exceptionally bad problems with surface-mount capacitors. All TE units should have their capacitors replaced as soon as possible. Without total capacitor replacement, a Turbo Express unit is guaranteed to fail.
In the past it was common to only replace the caps related to audio or to the display. Really all of the caps will be bad, so it is in your best interests to replace them all.
One more time: Do not replace only audio or display caps! Change them all!!
Everything listed here is contingent on 100% capacitor replacement. If you're repairing a Turbo Express with original caps, you need to change them before doing anything else. They cause a litany of unsolvable problems.
- Using batteries, image is bright or brightness changes in time with sound
- Replace batteries or test with A/C adapter.
- Display backlight does not turn on, fuse may or may not also blow
- Check for shorted transistor Q900 / Q901
- Turn on/off randomly when using wall plug
- Damaged DC jack or DC plug - see the #A/C Adapter Connection note below
When installing one of our leaded kits, with the exception of the 100uf 16v replacements, most caps should be installed laying flat.
CC100 100uF 16v CC101 33uF 6v CC102 33uF 6v CC103 100uF 6v CC104 100uF 6v CC500 100uF 16v CC501 4.7uF 35v CC502 4.7uF 50v CC503 22uF 35v CC504 100uF 6v CC505 100uF 6v CC700 100uF 6v CC702 470uF 6.3v CC703 100uF 6v CC704 10uF 16v CC900 100uF 16v CC901 22uF 6v Controller PCB Cap: CC800 47uF 6.3v
- VR500: Horizontal Sync / Horizontal Centering
- This adjustment moves the screen image left & right. Adjusting too far will destabilize the picture.
- VR501: Vcc adjust
- TE units are not restricted to TTL voltages. The factory setting seems to be around 4.5V.
Modification provided courtesy Bill McDonald
There is a pad on the top right of the board labeled BLH, if you remove the solder jumper from those pads, the onboard backlight turns off, which should save a bit of power.
A/C Adapter Connection
Both the A/C Adapter jacks, and the A/C adapter connectors seem to flake out and become unreliable.