68kMLA Classic Interface

This is a version of the 68kMLA forums for viewing on your favorite old mac. Visitors on modern platforms may prefer the main site.

Click here to select a new forum.
Macintosh Plus Chirping Noise
Posted by: MacintoshMan1999 on 2017-10-19 04:04:42 Here’s a photo
Posted by: techknight on 2017-10-19 16:05:47 first time I ever knew there being a fuse inline a wiring harness. Go figure.
Posted by: tomlee59 on 2017-10-19 16:14:54 That's also a first for me. Thanks for the pic. I'll have to open a few units and see how common this is/was.
Posted by: bibilit on 2017-10-19 23:01:37 https://68kmla.org/forums/index.php?/topic/13254-mac-plus-clicking/page-2
Posted by: MacintoshMan1999 on 2017-10-21 13:20:11 Update: I checked the continuity of the wire, definitely the fuse. ill post pictures
Posted by: MacintoshMan1999 on 2017-10-21 13:54:25 Here they are
Posted by: MacintoshMan1999 on 2017-10-21 14:02:23 Also, on the crt was this red stuff important?
Posted by: techknight on 2017-10-22 07:27:46 the picture you have linked is a projection CRT? Projection CRTs it is very important. Not so much on regular CRTs.
Posted by: MacintoshMan1999 on 2017-10-22 09:25:38 So the Mac Plus crt will be fine without it?
Posted by: bibilit on 2017-10-23 00:36:10 Yes, you can remove it or not, will work anyway.
Posted by: MacintoshMan1999 on 2017-10-23 05:11:49 Alright, Do you purchase your components from mouser?
Posted by: MacintoshMan1999 on 2017-10-24 17:40:57 Update: Just purchased two fuses, waiting for it to arrive.
Posted by: EkriirkE on 2017-10-25 00:06:48 Just want to throw out there, I had a 128 with a similar problem and it turned out to be a blown & shorted diode in the HV circuit https://imgur.com/gallery/fYSUd
Posted by: EkriirkE on 2017-10-25 00:09:03 Also, on the crt was this red stuff important? That's just silicone sealer to prevent possible arcing form the HV lead to the ground coating. Not necessarily required and I don't remember any of my macs having it. RTV silicone will do if you want. It was common in TVs.
Posted by: MacintoshMan1999 on 2017-10-25 17:43:21 That's just silicone sealer to prevent possible arcing form the HV lead to the ground coating. Not necessarily required and I don't remember any of my macs having it. RTV silicone will do if you want. It was common in TVs. Alright, thanks ill look into that I did notice the anode cap moves around, would the RTV Silicone prevent that?
Posted by: bibilit on 2017-10-25 22:51:17 I did notice the anode cap moves around, would the RTV Silicone prevent that? doesn't matter..
Posted by: MacintoshMan1999 on 2017-10-27 11:13:13 Update: I replaced the fuse in the wire and i'm still at the same problem. Although I have noticed that when the power/video cable is NOT connected the analog board makes that high pitch noise coming from the large transformer on it, but when it IS connected the speaker starts to make the same noise the transformer does. And lastly when I turn the Mac Plus off slowly, the CRT makes that static electricity noise that CRT televisions make when you turn them off. I'm going to look at The Dead Mac Scrolls again to see anything else...
Posted by: MacintoshMan1999 on 2017-11-06 12:46:25 I looked in the The Dead Mac Scrolls and it said that the analog board is out of adjustment and needs to be adjusted back to 5.0v DC, but when i try to set the voltage to 5.0v DC the reading on the multimeter goes all over the place and i cannot get a solid reading. Any thoughts on what could be happening?
Posted by: bibilit on 2017-11-07 00:34:43 AFAIK adjusting that resistor is a bad idea, unless you have replaced some parts around and you want to tune voltages. tuning it will increase the 5 volts, but also the 12 volts line, which can be dangerous for the board. Can be dangerous for yourself also, you are dealing with high voltages.
Posted by: MacintoshMan1999 on 2017-11-08 17:13:52 Hmmmmm... Well then I'm not too sure what to do. Well, I'm going to list all the events that have taken place since this project's start. There was a craigslist post I saw about a working Macintosh Plus, Imagewriter II printer, and all of the start-up disks plus manuals for $75.00 (it was on the site for quite a wile). So I contacted the seller and asked if it was still for sale, he said yes and that there was another guy from NY who also wanted it so if i could meet up at a certain time it was mine. So I said ok to the time and then went to pick it up, When I arrived he greeted me and showed me the boxes and its content, he then took it inside plugged it in and was going to demonstrate it but the screen was blank and it was making the "errrrrrrrrr" noise. I then asked if he could lower the price to $50.00 he then said yes. So I paid him the $50.00 and took it home. When I plugged it in and flipped the power switch it made the "beep" startup sound but the screen was not displaying a picture, so I found out that if I sharply tapped the left side of the case there was a picture and the mouse and keyboard seemed to work fine. Although I do recall that I probably did something stupid, when the external disk drive was out of the case I plugged the connector into the floppy port (stupid decision) and then the computer went into it's current state (no picture, start-up beep, and the high pitch chirping and ticking ((when up close)) started.) I then tried to figure it out/troubleshoot by myself and I did then mess with the voltage resistor (foolishly), at this point i did not know what else to do so i became a member of the 64k MLA and then asked for help. (which I highly appreciate ;D I replaced some of the components suggested by you and one of them was faulty, the fuse in the wiring harness (which i think is what the floppy disk drive triggered). And now I'm here, Hope this information will help. G'nite!
< 2 >