Repost worklog from Speleo about Asteroids Game PCB repair

Found a nice worklog about a Asteroids Game PCB repair. In german only

Reparaturbericht

Problem Beschreibung
Platine ist in brauchbarem und relativ sauberem Zustand. Es sind die üblichen Zusatzverbindungen und –änderungen bei diesem Modell vorhanden. An einer Seite sind sehr viele Abblock-kondensatoren nahe dem Abbrechen. Es handelt sich um die 8x2708 EPROM Version. Nach dem Anschließen an „Meteor-Adapter“ und XY Display resetted die Platine im normalen Modus (piept). Ein Wechsel auf Testmodus gibt ebenfalls rhythmisches Piepsen.

Reparatur Prozess
Da aus dem Piepsen nicht das defekte RAM herauszuhören ist (k.A. warum), wird das RAM mit dem 9010A Fluke getestet: 0000h-03FFh –> OK, 4000h-47FFh -> zahlreiche Errors, aber nur auf D4-D7. Nach Schaltplan dann die beiden 2114 RAMs auf 2D/2E ausgelötet, Sockel und NOS RAMs installiert – RAM 4000h-47FFh nun fehlerfrei.
Nach wie vor Piepsen, aber eigentlich sollten wir nun eigentlich einen Testscreen sehen, auch wenn das Rom defekt wäre… Ein wenig Wackeln zeigt Kontaktprobleme zwischen Sound/IO PCB und Backplane Stecker, intermittierend ist das Piepen weg und der Bildschirm zeigt wenigstens „etwas“ (mehr dazu später). Irgendein Kleber auf ein paar Kontakten. Mechanisch und mit Spiritus gereinigt. Danach ist’s besser, aber die Sound PCB mag es immer noch nicht, wenn sie ganz eingesteckt ist, lieber ein/zwei mm heraus aus der Backplane. OK müssen wir mit wohl damit leben, die Stecker der Backplane sind nicht handelsüblich.
OK, zur Bildschirmausgabe, die wohl ein Muster zeigt, aber anstatt gerader Linien einen Wirr-Warr. Ein wenig Messen zeigt uns verdächtige X und Y Signale bereits an den Operationsverstärkern direkt nach den DAC - Digital-Analog-Convertern. Die Eingänge der DACs schauen dagegen gut aus. OK, 2 x 24 Pin DACs auslöten, Sockel installieren und neue DACs (sind teuer) -> Bild ist gut.
Dann noch die Abblockkondensatoren getauscht, die brechen alle bei der nächsten Berührung ab, die EPROMS verifizieren und Flussmittel entfernen.
Ein letzter Test ist ok. Nicht getestet werden kann das Umschalten der Buttons auf den zweiten Player im Cocktail Modus (zu aufwändig einen Adapter dafür zu machen) und auch der Life Sound nicht, der normalerweise nie Problem macht.

Info für Lesie: Da, zumindest am Anfang immerhin noch ein gutes Bild da war, sind die DACs wohl seit der ersten Inbetriebnahme nach den 15 Jahren defekt gegangen. Wenn die Messungen oben am 16. Juni richtig sind, muss der Fehler im -15V Powersupply beseitigt werden, sonst sterben die DAC800 wieder, sie sind bis max. -16,5V spezifiziert (Messwert -20,3V). Dazu wird mindestens die im Bild markierte Platine benötigt.


25. Juni 2013 – Netzteilplatine ist eingetroffen. Spannungsregler 7915 hat wie vermutet satten Kurz-schluss zwischen Ein- und Ausgang. Spannungsregler ersetzt und getestet -> 14,86 Volt -> OK! Dann noch zwei Kontakte am angelöteten Stecker ersetzt, die angebrochen waren – blaues Kabel -5V.

Atari Asteroids Restoration : New sillk screened CPO

Hey,

 okay, this post is about the assembly of my new repro silk screened CPO. The old is 34years old. In fact I`d liked the wears of the old one, but anyway... finally I decided to swap.

I`ve made some pics while the game was turned. There was a neat effect on the screen while taking the pics. Hey, it`s a vector game :)

 

 

Atari Asteroids Restoration : New Control Panel

Thanks to takeman. The new CPO is silkscreened, no adhensive foil!

Asteroids : Wood work

Time to start  the wood work on the Asteroids cab.

Todo list for today :

 - Replace all parts of the backside
 - Add a second speaker
 - Add wheel for easy movement of cab
 - Add slider protection to prevent scratches on the floor.
 - Add PSU cable plug
 - Add Cab switch
 - Fill and Paint defect parts of the side walls.

 First the filling of the holes in the side walls.

See filled holes. I`ve made cuts for the wheels in the bottom, added slider protections and removed the old feets.

 

I had to relocate the PSU because of adding the wheels. 

I removed the old lower back plate and added a custom one. This one now has an additional on and off switch, a plug for the PSU harness and two big wheels.

okay, now to the upper back part. I`ve made an more or less exact repro ;).

 Now to the middle back part. The old one is broken.

this is the old wooden part with the stickers. It will be replaced, too. Sadly I do not have this type of stickers :(

After disassmbleing the complete cab, cleaning, wood working and building all the stuff together this is the result of this day. The middle is left plus the sticker.

Have fun.

Asteroids : Scanning sidearts

Hey,

since it was very difficult to find sideart vectors  for the Asteroids I`ll do it myself. I`ve buyed a new flatbed scanner. I was inspired by this tutorial and Etienne from the DL forum

Sideart Scanning

I scanned 26 pics on 600dpi each 110MByte. I`ve now 2.5Gbyte Asteroids scans :)
 

Have fun

Asteroids - Push Start

I`m happy. After tons of reading, measuring the first astreoids PCB works. So I`m looking forward to get my own one to work.

But this is the break thru : Power Circuit work including fuses, PSU and ARII, Vector Monitor works, Deflection PCB and Chassis works plus harness.

Asteroids Cab close ups

just the uncommented pics

Asteroids PCB findings

Hey,

 okay, my gameroom took some time so the Asteroids Restauration had some days off.

Finally I`ve now again some time to spent  investigating the PCB. Last known state was, that PCB isn't working with black screen and no sound.

Step 0
So I built a PCB connector giving 30VAC, 5V and GND to the PCB. For the first tests I only need 5V and GND:

Step 1
 With this setup I measured the MCU Pin40. My Logic Probe is blinking here, means the PCB makes a continuous reset.

Step 2
So I checked the ROMs. A rom compare shows that all roms are OK (vers.1)

Step 3
Cut the vector state machine generation from the CPU. To I cut Pin1 from IC L6. The reset line is now high.

Result : The PCB has an error in the vector generation circuit. Means also, that the CPU is working and that the circuit for watchdog / reset generation is working. Thanks to Speleo for helping me with these findings.

 

Since the vector state generation circuit is a very ttricky one I give the PCB to speleo. Hope he can help me.

Next the vector video output :) Cebulba gave me a working Asteroids PCB. This way I can continue testing the deflection board and power circuits finally.

Check the deflection board

Step 0 : Eye Check :
The silver color Elko right hand side is damaged and was ripped somehow. Afterwards it was glued. So perhaps this one must be replaced.
The poti for brightness control is totally screwed up. Replace it.
The poti for contrast is not destroyed, but is rusty. Replace it.
All connector solder points must be resoldered. The solder is very old.

Step 1 : Measured the transistors: No short between E and C. Putting the multimeter to diode setup and measured the diode voltage between base (B) and emittor (E). It should between 0.4V and 0.7V. Done this for all transistors. Take a look at the numbering of the parts. The first number denotes the circuit for generate x and y (and z?). Measure the diodes, too.

Here was everything okay.

Step 2 : Measure ESR of Elkos. All Elkos ok,  (low esr value).

I decided not to connect the deflection board, coz I`m waiting for the Poti. Without the poti further in system testing makes no sense.

Check of power system

Step 0 : Put the known working PCB in the CAB and turned it on. No sound.Add some coins and pressed player 1 start. Coin buttons showed some behaviour. So again the question why sound is missing?

Step 1 : Checked wiring of speaker. On wire was not connected. Connected it.

Result : PCB plays blind. :)

Did some further measuring of voltage on PCB x and y ouput -> jumps between 1-4V-7V somehow.

In summary this was a big step. A working PCB plays blind and I have some idea to make further progress on the deflection board. Game PCB must be repaired either the way.

Asteroids Restauration : knee deep in the chassis

Okay, some more infos for the Asteroids Chassis G05-801

- Regulator PCB

P100
Pin 1; 28VAC
Pin 2; GND
Pin 3; Filament GND
Pin 4; 28VAC
Pin 5; GND
Pin 6; Filamnet 6.3VAC

P101
Pin1, Pin2 ; 25V/35V
Pin3, Pin4; GNd
Pin5; -25 / -35V
Pin6 ; Key
Pin7, Pin8; 6.3VAC



- Deflection PCB

P703
Pin1; x; +/- 10V
Pin2; GND
Pin3; y; +/- 7.5V
Pin4; GND
Pin5 ; z; 0.5V blanking, 1.0V off, 4.0v full on
Pin6; Kex
Pin7; GND


- EHT Supply PCB

do not touch

Asteroids Restauration : knee deep in the ARI Board

PSU was fine. Next one is the ARI Board. First as usual tons of reading.

Obligatory Bob Roberts Link
Asteroids Manual
Page 32 for the schema, page 33 for the parts list.




ARI boards handle 5V regulation for game PCB and audio amnplifier. So measure the regulated 5V vs GND VDC.

Since I`m facing psu issues first, I`m taking a closer look to

C1, 470uF, 25V
Q1, LM305
Q2, TIP32
Q3, 2N3055

and of course 5V vs GND

J7
pin5,6 vs GND
pin1,4 vs GND

Additon : just found a good pic

Atari Asteroids : knee deep into the Power Supply Unit

Okay,

this is my little friend I was in touch yesterday : The Atari Asteroids PSU:

First did some cleaning.
Replaced F5 and did some measuring. Noticed that the schematics was somehow tricky and reworked the figures of the manual.





Measure point of GND is blue spot in Fig 3.

Measure points of fuses is the red spot. This should be the values

F2 vs F3 (7A)= ~15 VAC (VDC after diode cr1, cr2)
F2 vs F3 (3A)= ~36 VAC
F6 (3A) vs GNS= 6.3VAC

Measured

F2 - F3 -> 21V
F2,F3 vs GND -> 10,5V

F4 - F5 -> 38.3V
F4, F5 vs GND -> 19.15V

F6 vs GND : 14.45v

F6 vs F4 : 31.8V (yellow cables)

For first okay, since the load of the monitor is yet to come.

http://www.therealbobroberts.net/apsnotes.html