|
|
Post by viperz on Aug 4, 2021 16:56:34 GMT
Hi Norman, TR1 is the one in coin register mech, right? I'll pull the coin register out and inspect... I did install the new 100uF cap across that relay coil a few months ago... I can definitely swap it for a smaller cap.
What bothers me is that those are SB fuses, so length of the pulse technically should not be long enough to blow them. I have been playing songs on this jukebox since this morning, so a few hours no, with no issues...
|
|
|
|
Post by Ron Rich on Aug 4, 2021 17:36:47 GMT
Eugen,
What circuit is that fuse in ?
When it's open, and you press a selection, does it release, or not release the selected pin ? Ron Rich
|
|
|
|
Post by viperz on Aug 4, 2021 18:25:18 GMT
|
|
|
|
Post by jukenorman on Aug 4, 2021 19:39:00 GMT
Hi Eugen,
I don't have a 1900 manual. The circuit you posted describes phase 7. Could you post the circuit that shows the current flow (shown in bold) through the fuse, TR1, TR2 and the pushbuttons to the selection coils - so that we can read what the attached blurb says.
Norman.
|
|
|
|
Post by viperz on Aug 4, 2021 19:52:00 GMT
Hi Norman: here it is: photos.app.goo.gl/FksUCkFB8saMbgUB8[edited] So looking at other steps, TR1, and TR2 are all powered by 28 VDC, not 24 VAC from this line... This is the only line that shows 24VAC going through the circuit. Also, the counter coil is in this circuit, but not protected by this fuse. Am I correct to assume that this 400mA SB fuse only protects the 26 selector coils in the Selector unit? The current only flows through this circuit and selector coils only when letter/number are selected... I have 10 records loaded, and played those 20 songs one by one multiple times all day today with that fuse not blowing. Does it mean that it is not the selector coils, which are causing the problem? But if that's the case, there is nothing else in this circuit... Even if selector coils get stuck for a few milliseconds longer, why would this fuse go? |
|
|
|
Post by jukenorman on Aug 4, 2021 20:39:50 GMT
Hi Eugen, First of all, the 100uF capacitor has no bearing on the fuse blowing so you can forget about that! Having read the blurb and decided your issue is with TR2 and its shorting rings, I did a search of the site and found a thread on a 2204 blowing the 0.4A fuse - you could try the solution that the poster of that thread decided cured his problem with TR2. I actually think it's not unreasonable that your TR2 might be a bit sticky to release especially if it's been sat for a while, so it might well work! jukeboxaddicts.proboards.com/thread/1299/w2204-selection-issues-blowing-fuseNorman. |
|
|
|
Post by viperz on Aug 4, 2021 20:50:31 GMT
Hi Norman, thank you again... ha, so all that guy did was clean between coil and plate because he had some oil there? So it was not even related to the shorting rings? I honestly don't even know what shorting rings look like, will go find my old photos. My buttons release after milliseconds, definitely not after a few seconds. However, in very rare cases I would push both buttons, but they wouldn't release at all - I'd have to push 'cancel' button. I never looked at that, as when the buttons are stuck, the fuse does NOT blow. It happened once today, buttons were stuck for a few seconds before I cancelled (I thought one letter contact may still have oxidation). The fuse definitely blows in my case during one of the selection cycles on cold... I have no issues with opening the junction box and re-cleaning TR2 coil, but I know I cleaned it before. Here is a photo of my TR2 when I first opened the box back in February... photos.app.goo.gl/szDcbkEsjNLNXukA6You know what.. next time this thing blows, I will open the box and clean between the magnet and the coil in the very back - maybe it is sticking there a little. But again, my sticking is not for a few seconds, even when the fuse blows the buttons release within milliseconds. |
|
|
|
Post by jukenorman on Aug 5, 2021 8:50:52 GMT
Hi Eugen,
You can see the copper shorting rings at the top of your photo. Acoording to your diagram, TR2 should provide a 50 millisecond pulse. The problem you have is that it's impossible to discern with the naked eye, the difference between 50 and 100 milliseconds - and 100 milliseconds might be enough to pop the fuse. In order to measure the pulse length, you would need a storage oscilloscope. So your best hope is to start with simple things like cleaning the relay.
In the 2204 thread, the OP used contact cleaner. If you use that type of solvent, clean it off with a rag after application because if a gummy product like WD40 has been sprayed around TR2 (and I'm not suggesting you did it!), you have to remove it or it will just revert to gumminess with time. I know we bleat on about WD40 but with good reason I believe!
If you're not convinced about the cleaning, have a look at the spring - see if it looks stretched which would have the effect of increasing the release time.
Actually, you might be able to verify roughly that it's a 50 millisecond pulse using a non storage 'scope. At 60Hz, you should see three full cycles for 50 milliseconds. Do you have access to an oscilloscope?
Norman.
|
|
|
|
Post by viperz on Aug 5, 2021 12:50:50 GMT
Hi Norman, yes, I'll definitely clean as you suggested (99% isopropyl alcohol, I guess) and will inspect the spring. I do have a regular scope. I guess, I can connect one probe to the coil, and one probe to the contacts and set it on the trigger. I just need a few more days to hopefully finish my current project and clean my main bench, then I can definitely concentrate troubleshooting this with all the good info you have given me.
|
|
|
|
Post by Ron Rich on Aug 5, 2021 12:53:11 GMT
Hi Guyz,
That type of relay had a "habit" of getting the armature "magnetized", along with picking up "dirt" from a WD 40 type,"cleaning". There are a couple of ways I deal with that. The armature must be removed, and cleaned (along with the pole piece), with either a safety solvent, and/or 91 % rubbing al-key haul. At this point, a -very- thin piece of Mylar tape can be attached (glued), to the armature where it hits the pole piece, or a small hole drilled in the armature, filled with a small brass insert. NEVER cut loops off, nor stretch ANY springs ! Ron Rich
|
|
|
|
Post by viperz on Aug 5, 2021 13:41:53 GMT
Thank you, Ron. I'll dig in to check both, TR1 and TR2, and will report back after cleaning and measuring.
|
|
|
|
Post by viperz on Aug 22, 2021 20:43:14 GMT
I finally found time to dig into this jukebox. Went through the whole 24VAC circuit, inspected all wires and relay contacts. The only things worth mentioning that I found was black dirt in the TR1 and TR2 coils... cleaned it all out with a piece of paper soaked in alcohol, multiple times. Also cleaned the contacts on both relays again - TR2 had dirty contacts, I was pretty sure I cleaned them earlier this year. The jukebox was off for a couple of weeks, fired right up and playing now. Will see how it performs.
|
|
