I’m heartbroken! I just replaced the battery in my Juno 106 and now… NOTHING. Won’t even power on. I have checked all the connections and everything looks fine. I checked the power supply and all voltages appear to be correct. It’s almost as if the CPU isn’t firing up or resetting or something like that. Any suggestions?
check all voltages in mainboard
Thank, kapil. I have checked all the voltages on the power supply.
+5 - Good
+15 - Good
-15 - Good
+9 - Good (Reads at 10.1, but I’ve seen that seems to be common)
Do you know where on the CPU board to check the voltages? There aren’t any obvious Test Points marked on it.
I would check cpu reset signal…a lot of them need voltage applies after a delay using capacitors
+9v isn’t sounding right
I see +/- 5 and +/- 15 on adjustment guide
Looking at the schematic, the +9 volts isn’t regulated, so it doesn’t surprised me that it’s higher, but I’m going to check that reset circuitry to see if it’s actually doing what it’s supposed to. Thanks to everyone for their suggestions! I’ll keep you posted.
Whoo hoooo!!! It lives!!!
First of all, thanks to everyone for their help. What a great community!
Second of all… I’m an idiot! LOL When I took out the CPU board to swap out the battery (and put in a battery clip at the same, I accidentally got two of the connectors flipped around (the 8-pin CPU power/reset connector and one of the 8-pin display connectors). I discovered this after finding an online service manual and started following the wires from the power supply. They didn’t go where they should have (big surprise). Fortunately, no damage seems to have occurred from firing it up with those connectors reversed, so all is well. She lives to sing another day!
For those who may be interested, this is the service manual I found:
Roland Juno-106 Service Manual.pdf (kiwitechnics.com)
THIS is why you always apply the KISS principle! lol Once you had the MANUAL, which is the FIRST tool you get with any machine and read it to have something to compare to you know is right, then this wouldn’t have happened. As you said, luckily there was no damage, but thats not always the case…I’m inside a JX8P doin a recap and upgrading the bridge rects and even though i could do it blind and one handed I have the manual on my tablet and goin at it one section at a time and double checkin the work. gettin inside boaurds is not for everybody and bein a Harley and vehicle mechanic/machinist i find working with small parts highly irritating so I wouldn’t attempt a repair or upgrade without a manual/KISS principle ever…