Side note: Replacing the tube was something I did while I was troubleshooting another problem: dim vectors that I could barely see. Using the Cinematronics Vector Monitor FAQ, I tried a few different things, but the tube and video board appeared to be fine. The “dim vector” problem stemmed from the BRIGHT/INTENSIFY circuit on the main game board. (The “Intensify” [Connector J2 pin 12] and “Bright” [Connector J2 pin 14] outputs on the main board didn’t show activity with a logic probe. These dead outputs led to the dim vectors.) Also, the IC at F2 (a 74LS259) was SUPER hot to touch, which is usually a tell-tale sign of a bad IC. F2 is responsible for a few things, including the control panel and… brightness. I replaced it, but that didn’t solve the problem (even though F2 ran cool after that.) The PROMs (C14, D14, E14, F14) were also hotter than the other ICs, but this is apparently normal. I couldn’t figure out the problem, so I had to send the board to Mark Shostak at Cinelabs. He fixed it — the problem turned out to be the IC at location E6, a 74LS163 binary counter that’s part of the LINE DONE circuitry. The LINE DONE circuitry feeds the INTESIFY and BRIGHT circuits, hence the dim vectors.

Back to the picture tube… here’s the replacement information:

Richardson Electronics
1-800-238-7661 (Personal Sales Phone Number)
http://www.rell.com/
Part Number for Tube: 19VARP4

Even though the website listed that part number as “on order”, the rep I talked to said it was in stock. They sent it UPS Ground and I received it a few days later. (They’re in IL, right outside of Chicago.)

Replacing the tube was very easy. Of course, you must DISCHARGE the tube before removing it! Don’t touch the tube or work on it unless you know how to handle a picture tube! There are 4 bolts the hold the tube in place so you can remove and drop in a replacement tube. All I had to do on the tube was unsecure the yoke from the old tube and move the yoke to the new tube. Before tightening the yoke on the new tube, while the game was on I rotated the yoke a bit to make sure the image on the tube was straight. Then, I removed the color screen overlay from the old tube and placed it on the screen of the new tube. I had to remove the old “black sticky tape” and use 3M double sided tape (the “cushion” kind) to stick the overlay onto the new tube.

With the game on, I moved the magnets (those little levers on the end of the yoke) to center the image under the overlay. After everything was lined up, I adjusted the brightness (R11 on the video board.) Everything was perfect after that! The new tube made a world of a difference. The tube warmed up instantly and the vectors were now crisp, clear, and bright! It definitely made the game look brand new.

The first rule of thumb (which I stubbornly ignored this time, unfortunately) is to check all the voltages. I wish I did this first, as it would have saved me tons of time. The sound effects above use a few ICs in common, one of which being the Noise generator, IC14. It looked like the Noise generator wasn’t supplying the needed noise for these The Noise generator is one of the few ICs on the sound board that uses +15V. I checked IC4 (the +15V voltage regulator) and sure enough, it was registering +30V! IC4 was bad. I ordered a replacement 7815 from Mouser, and this fixed those sound effects.

I looked at the “Background Sound” circuitry, but more closely at where +15V feed is. If the +15V had been bad, maybe it fried something in that part of the Background Sound circuits. Sure enough R2 (a 1/4W 160 Ohm resistor) was burned and registering 0 Ohms with my digital multimeter. I replaced this resistor, and now the Background Sound works. The Star Castle is now fully operational again!

I started with the board I recently fried. The Star Castle tech manual has an excellent section on troubleshooting the sound board (page 6-9). An oscilloscope is an absolute must for troubleshooting this component, as this is where all the analog signals are generated. A logic probe isn’t going to be much help here! I used an oscilloscope to look at the final amp outputs and inputs. The display on the ‘scope looked like someone was shouting into a microphone at a subway station. No matter where I probed in the final amp stages, it was not a pretty sight on the ‘scope. I decided to put that one aside and check out the sound board from eBay.

I noticed that two of the resistors were burned at locations R122 and R124. These are 150 Ohm 1/4 Watt resistors. I replaced them, hooked up the board, and powered on the game. The resistors promply burned black as soon as I coined up the game. I powered the game off, and started troubleshooting. I first checked the volume pot located on the coin door with a multimeter set to Ohms. The pot checked out OK. I then check the speaker with a multimeter set to Ohms. If the speaker shows some resistance, then it is ok. In my case, the speaker would not read anything on the multimeter. I checked for continuity, and the speaker was “open.” I had blown the speaker! (On another note, if the speaker had no resistance and the curcuit was “closed”, this kind of short can also cause damage to the final output circuitry on the sound board.)

Since the volume pot was ok, and the speaker was open (as opposed to shorted) I replaced the following ICs responsible for the final amp stage (I ordered these from Mouser Electronics):

Q17: 2N6292
Q18: 2N6107
IC25: TL081

I also replaced the resistors R122 and R124 that I had burned up in the last power on. After replacing those components, I powered everything on, and none of the resistors burned! This was promising.

Now I went to the final amp circuitry on the sound board with my ‘scope. I first checked pin 3 on IC26, which is the input to the final amp circuit. On the scope, (instead of lots of noise like with the previous sound board) it looked like this:

Which is good! I then checked pin 3 on IC25; this is the signal return from the volume pot on the coin door. I didn’t see anything on the ‘scope. Oops! I forgot I had turned the volume down when I was checking the pot with a multimeter before. I turned the volume up, and I saw the same waveform on the ‘scope as when I was checking pin 3 on IC26. I then probed the junction of the emitter and collector on Q17 and Q18, which goes to the speaker. I then saw a nice waveform on the ‘scope. I hooked up a good speaker, and voila! Star Castle sound effects.

To replace the speaker I blew, I had a heck of a time trying to find a replacement. I was looking for a full range 8 Ohm 8-Inch speaker. Not a low frequency range woofer, but one that can handle a range near 60-20,000Hz. To my disappointment, Radio Shack doesn’t sell replacement speakers any more! After some searching, I finally found a supplier at Parts Express in their menu: Speakers -> Pro Sound Drivers -> Woofers Up to 8″. They had the QSL QS08R10 8″ Driver for $9!

Read my next post on the subject, where I discover (and repair) some other problems with the sound board.

A couple months later, with purchases from eBay, Mouser Electronics, and *tons* of help from Mark Shostak [Cinelabs], I plugged it in. (Mind you, I had already “plugged it in” for the umpteenth time with all the troubleshooting I was doing…) Anyway, where was I? Oh yes. A few crackles from the speaker. The hum of the picture tube. And there it was… something I hadn’t seen since 1982. The Star Castle, with its three counter-rotating shields, faded into view and quietly beckoned:

Mark Shostak [Cinelabs] was highly invaluable for helping me restore Star Castle. He was very nice, repaired my sound card for a flat rate, and even guaranteed it. Not to mention all the helpful e-mails he sent answering my tech questions. If you have any Cinematronics game out there, and you need it repaired, e-mail Mark at sales@cinelabs.com.


Arcade Stats:
Manufacturer: Cinematronics
Year Released: 1980
Cabinet: Upright
Monitor: 19-inch Horizontal Vector
Coin Counter: 21106
Tony's First Quarter: Great Skate, Norwich, Connecticut