Fixing Sea Raider Sound Issues

I have a 1969 Sea Raider that I bought earlier this year.

IMG_7428 IMG_7429 IMG_7432

It has been mostly restored already as you can see from the pictures.  It does need some minor work, but it is in good working condition.   The top back-glass is in pretty good condition, but the windows that observers can watch you playing your game through are a little scratched up – I think probably from someone scraping off a sticker or tape with something that was too sharp.   The bottom back-glass is in very rough shape.   I’m not sure if someone tried to clean off the back of this glass and removed the paint, or if it just fell off on its own, but either way, it’s difficult to make out most of the original art.   I’m not sure if I will get these reproduced or not.


View through the observation window


This is another game I remember from the skating rink when I was young.  Probably from 1975-1979.

It is completely electro-mechanical except for the sound.   It has some simple circuits that produce 1) a sonar “ping” sound, 2) a torpedo “swooshing” sound of the torpedo launching and going through the water, and 3) an explosion sound when the torpedo hits a ship.

This game’s sound is working, but the explosion didn’t sound like I thought it should.   It would make 2 quick ‘banging” sounds that were vaguely like an explosion, but just not like what you’d hope for.   When you are firing a torpedo and hit another ship, there is a certain satisfaction that comes from a good explosion, so this had to be fixed!

I found an article where someone else was documenting repairing the sound on their Sea Raider.    Luckily, the parts were all present on my machine.


In my game, the 500mfd capacitor had been replaced (I could tell because it was newer, plus it wasn’t soldered in (also, it was only 470mfd).   I guess the previous owner must have been trying to fix it also.   But even though they had replaced the cap, the sound still wasn’t quite right.   I started to do some diagnosis.   I tried larger and smaller value caps with no change in the sound.   Then I tried with no cap – same sound.   Obviously something else was wrong. I didn’t have a schematic, but as far as I could tell, there was only one other component in the that circuit – a really old diode.  This picture shows the cap and diode.


I figured the diode had to be bad so I removed it and tested it.   It measured 2 ohms resistance in both directions… that’s not right.   I looked up the specs and found a similar diode in my stock and soldered it in.   That was it, now the sound was working correctly.   I think I need to go up to a 500mfd cap because the game is supposed to have a 2-3 second explosion, but the delay I’m getting with the 470 is about 1.5 seconds.   A little longer would be nice, but I don’t have a cap rated at the right voltage on hand so that will have to wait.

Pictures for Evan


Close of up cap circled above.   I twisted it around to see the writing on it.


The cap circled above looks to be a 1000uf 25v electrolytic.

The other item circled looks like a diode with “H640” written on it.   Here’s a picture.


IMG_9965 IMG_9964 IMG_9963 IMG_9962 IMG_9961 IMG_9960 IMG_9959 IMG_9958 IMG_9957 IMG_9956

IMG_9966 IMG_9967 IMG_9968 IMG_9969 IMG_9970 IMG_9971 IMG_9972

32 thoughts on “Fixing Sea Raider Sound Issues

  1. I’ve restored this game got the sound working like new if you got any questions feel free to ask. Just saw your sight u do nice work.

    • Thanks for the kind words! You do some very nice work – I’ve seen some of your restorations on pinside and klov. I may take you up on your offer, I still don’t think my explosion sounds like what I remember this game sounding like back in the day.

      Are you in kc somewhere? I’m in Lenexa, and work downtown.

    • I have one no sound I would really appreciate any insight into fixing it speaker is good

    • I need help on my sea raider. What cap makes the ping sound? All sound work but that. It just makes a tick tick sound.

    • Hi Evan, I published some pictures of the two components you circled up at the end of the post. Have a look, hope they help.


      • Here’s my board some of the components are burnt and my capacitor is missing I saw your pictures but I’m still not sure what the capacitor I’m missing and that burnt component is

        • I’m pretty sure the burnt component you are talking about at the bottom of the board is that Diode I listed above (at the bottom of the post). I can’t tell for sure from the picture, but it looks like someone has cut out the capacitor and replaced it with something. I can’t tell from the picture you posted what it is – I’m referring the the circular metallic looking item in the “missing cap” circle above. Maybe you could take some more pictures of it from different angles? It kinda looks like a potentiometer or variable capacitor. I can see the lead from the original capacitor where it was cut (I think) on the far right of the circle you drew. I suspect you can remove the circular metallic item and solder in a new 1000uf 25v electrolytic capacitor (which should be the missing cap you are referring to).

  2. Not at all :-). I did quote a bit of googling to see if I could find a cross reference for that diode. I couldn’t find anything. Since it’s in the area of the board where two hint sink mounted transistors are, I suspect it’s part of the amplifier circuit. I’m not super familiar with the design of these types of circuits, but I would probably just try a normal high amperage diode like a 1N4006 or 8 diode and see what happens. I wish I had a schematic…

    • OK I just put in the diode and new caps. And turned on the machine and the board put a load on the transformer and blew the 6 amp fuse and burnt the diode to a crisp I wonder if I put the diode in the wrong direction?

      • whew! man. That sucks, but I suspect you’ve found the reason the diode fried in the first place. I’m guessing those transistors (one or both) are shorted. I found some posts about modern replacements for them. Check this out!topic/ One thing to consider, you could also just replace the old amp board with a new off the shelf small amp… depends how original you want to keep it…

  3. Peter great post ,especially since I just picked up a sea raiders the other day ,got most of it working but no ship in area lights, any ideas how this works and no sound,the spring for explosion sound is missing and I can’t see the little ring that protrudes from the bottom of the Transducer? That is mounted on the top of the board, I think I read somewhere else someone used a metal guitar string for this could I just solder a guitar string from the top of this and shape the bottom into the ring to attach the spring,also what type of sprint can’t be much tension and where do I attach the magnet ,also missing,top or bottom of spring and how large a magnet .
    Finally that diode you mentioned is also fried on mine. Could this be why I get no sound?
    I will try to get the diode you mentioned and get those two transistors just incase,suggestions for sources of these parts?
    Thanks very much ,very helpful

    • Hi Jim,

      Digikey, Mouser, Jameco are all good sources for parts. There are also a number of good surplus electronics sites that are good like

      There are some pretty good pictures above of the area you mention. If you click on them they should expand to show a more detailed picture. I think you can pretty clearly see the spring, it’s attachments, pickup etc… let me know if you’d like some close-ups or more specific shots.

      I think the spring is bigger than a guitar spring, although one may work. I’d guess it’s about 1/4 inch in diameter.


    • Thanks for the reply.replaced the diode and a bad cap,then I noticed that between the two transmitters that were mentioned above ,it looks like there is a Grey componenet,mine is missing ,just 3 wires protruding from board ,what is this component ,how is it wired ,so I can get one and replace it ,
      Thanks again

  4. Thought I would post specs for the amplifier transistors that I found posted in another forum.

    The specs for the 2 are
    25V, 1A , 1.6W
    h(FE) min =70
    h(FE) max = 350

    The 4105 is NPN Power BJT
    the 4106 is PNP Power BJT

    Cross reference for older NLA parts
    2n4105 -> 2N2430
    2n4106 -> 2N2706

    Cross reference and spec sheets here:$$Search?OpenForm

    NTE cross reference

    2n4105 -> NTE103
    2n4106 -> NTE102

  5. Pete I’m not sure you saw my earlier post .I replaced the diode but noticed my board is missing that grey electronic component mounted between the two transistors mentioned in a prior post .you can see this component in your pics .what is it .how is if wired . thanks jim

    • Hi Jim, sorry I’ve not been keeping up too well 🙂

      I’m not really sure what that circular component is. It has 3 leads, and is located with the other transistors, so I’m guessing it is some kind of transistor, but I have no idea how to tell what it’s specs are. I just did a bit more poking around on the web but can find nothing. What we really need is a schematic for this board, but I’ve never been able to find one. I’ll keep looking to see if I can find anything.


    • Jim, I was looking at the picture of the part you are asking about again. When I look at carefully, now I’m not so sure it has 3 leads. I think it might just have two. Would you mind posting a closeup of what your board looks like? I’d like to verify this – and I’d rather not pull my mine apart again. 🙂

  6. Looks like I have three posts that were cut onine to remove the part here is a picture of the area. Does that mean it’s some type of transistor

    • I’m not sure what that is. I can’t find anything about it. I looked at schematics for typical amplifier circuits, but the only components I see other than the amplifier transistors are electrolytic and ceramic caps, and resistors. I have a feeling the two transistors and the component between them may be related to triggering the relay that controls the amp. I have a feeling they are just mounted to the same board as the amp, which I suspect is above. The only schematic I can find is for the whoosh and ping sounds, the board that is mounted ‘on-top’ of the amp. I’ll see if I can make some time to open the machine and measure the resistance/capacitance of that component to figure out what it is this weekend if that would help…

  7. Pete on closer examinaton it has two leads I think it’s a capacitor. One of the leads on the transistor to the right has one lead broken off . Are there markings on the transistor so I can see where the leads go when I reconnect the new transistor

    • I think you are right, I only see two leads as well. I’ve posted a bunch more closeups. Hopefully these help.

      • Thanks for your help if you ever get a chance to measure capacitance across that thing let me know what you get

        • Hi Jim,
          I tried to measure capacitance across this thing, but got 0uf. I tried resistance, and got 32ohms. Looking at the traces on the back of the card I can’t be sure I’m not measuring resistors in the circuit. Anyway, I guess it’s possible it’s a resistor, or even a thermistor.


          • I was just poking around on google, looking at vintage thermistors, and I’m really starting to think that that is what this thing is. It’s probably 32ohm cold. Here’s a picture of a similar item..look how similar it is.

  8. pete thanks for the help not sure you got my last message
    but i am going to replace at least 1 transistor but not sure where leads B,Eand C go
    i think lead b is the middle lead from the old transistor
    but not sure about lead e and c
    there is a blue dot on the side of the old transistor ,does this indicate the c lead ?

    • I’m not really sure. The transistors don’t appear to have any other markings besides the dots that I can see. Not sure how to tell.

  9. Ok it’s me again sorry I have a question about the Ping and the whoosh board could you send me a picture of the front and back of the board?

    • Hi Evan, have a look at the pictures above, there are a number of pictures of the board. Hopefully those give you what you need. Let me know if not.

Comments are closed.