I recently went through a similar exercise with my Q*Bert arcade machine. I was checking voltages from the transformer, at the power supply, etc. The whole time I'm thinking a bridge rectifier failed. Nope, just a fuse. Another reason to always check the fuse with a multimeter instead of just a visual check.
I learnt 2 good lessons from your video; 1) Don't measure the PSU with a potentially faulty load attached. 2) Simple parts (fuse, in this case) can fail in complex ways. So thank you for that.
Awesome. Sometimes the problems can be so simple. I've been tracking why my Linndrum doesn't play the kick for over a year now and still can't find the error.
@synthchaser I just retrieved a TR-808 from storage that is configured for 220V and I want to do this EXACT conversion to 110V! What perfect timing that I found your video
New Synthchaser video day!! 🎉. Question, you were about to check the fuse to measure resistance before it broke. What resistance value would be in range for the working fuse? Or was it just a continuity check? Thank you!
I kinda need to do the opposite: convert a 120V American Ensoniq ESQm to 230V European voltage. But the ESQm has a complicated transformer because of the VFD, not to mention that the service manual isn't very clear about the power PCB.
It's nearly always something in the power supply. Change to different primary voltage use generic 9V and 12-0-12 ones, doesn't have to be exactly same, line voltage varies by up to 20 percent and the heatsinks just burn off the excess.
doesnt that heat also stress other components though ? Im looking for a france to US conversion transformer. any direction towardss a generic would be aprec
@@COD-dr1ph To connect directly to US line voltage, exchanging T1 for two separate transformers of 9 VAC and 12-0-12, would have less deviation of voltage than the natural variation in line voltage. The heatsink has already burned off excess voltage for decades already. If it didn't burn off excess voltage then the voltage would go out of spec when the line input drops to 80% or whatever it is.
@@jagmarc my calculation says that 12 volt ac produces 15.6v DC after rectification. Isnt this a little low for the ta7179p to produce a consistent 15v +/= ? shouldnt there be more headroom ?(around 17vDC?)
@@COD-dr1ph a "12 volt" transformer puts out more than 12.0 VAC :) Hey, if does turn out lacking headroom you could swap the bridge for discrete schottky diodes with lower drop.
I had a problem with the 15/-15 fuses on a 106 recently, they were blown, but when powered on, voltage still made it to the other side!! Somehow become semi conductors. With the power off they were open circuit, powered on they passed a low voltage : /
@@newking70 the owners existing line voltage is 110v, the unit required 220v line voltage, so the owner used a step-up transformer to change line voltage from 110v to 220v. Now replacing the units existing internal transformer to one that has an input AC voltage of 110v eliminates the need to use an external step-up transformer.
a step *_down_* transformer would be used for powering a 100-120v appliance in a 220-240v country, whereas in this case, a step *_up_* transformer was being used to power a 220-240v appliance in a 120v country. he then simply replaced the 808's internal 220-240v-input transformer with a 120v-input transformer, effectively changing the 808 from a European one to an American one and eliminating the need to use an extra external (step up) transformer.
What blows my "fuse" is the fact that you replaced that one bad fuse with a fresh new shiney one and left the other 3 dull old ones in there... after complaining about the low quality junky fuses that were in it...
Synthchaser, you have mad diagnostic and troubleshooting skills! I love seeing how you whittle down a problem to an often simple cure! Thanks!
I recently went through a similar exercise with my Q*Bert arcade machine. I was checking voltages from the transformer, at the power supply, etc. The whole time I'm thinking a bridge rectifier failed. Nope, just a fuse. Another reason to always check the fuse with a multimeter instead of just a visual check.
I learnt 2 good lessons from your video;
1) Don't measure the PSU with a potentially faulty load attached.
2) Simple parts (fuse, in this case) can fail in complex ways.
So thank you for that.
The problem doesn't have to be complicated always...finding it without taking everything apart is the trick! Well done! Love your videos...
What an easy fix! Getting a bargain 808 for a simple bad fuse would be awesome.
Very good job of keeping a classic synth in operation ✌️
I like your thought process and trouble shooting. To see that a fuse that wasn't blown cause the issue was quite surprising.
Yo that beat is CRAZY son!
Interesting to see the inside of this classic machine.
Awesome. Sometimes the problems can be so simple. I've been tracking why my Linndrum doesn't play the kick for over a year now and still can't find the error.
You're going to want to watch my next video, then!
@synthchaser I just retrieved a TR-808 from storage that is configured for 220V and I want to do this EXACT conversion to 110V! What perfect timing that I found your video
As always, insightful and interesting. Keep up the excellent content.
I wasn't expecting so much empty space inside.
Love all your videos. Thank you.
New Synthchaser video day!! 🎉. Question, you were about to check the fuse to measure resistance before it broke. What resistance value would be in range for the working fuse? Or was it just a continuity check? Thank you!
another great video !! thank you!
Lots of fun 👏🏼
I kinda need to do the opposite: convert a 120V American Ensoniq ESQm to 230V European voltage. But the ESQm has a complicated transformer because of the VFD, not to mention that the service manual isn't very clear about the power PCB.
It's nearly always something in the power supply. Change to different primary voltage use generic 9V and 12-0-12 ones, doesn't have to be exactly same, line voltage varies by up to 20 percent and the heatsinks just burn off the excess.
doesnt that heat also stress other components though ? Im looking for a france to US conversion transformer. any direction towardss a generic would be aprec
@@COD-dr1ph To connect directly to US line voltage, exchanging T1 for two separate transformers of 9 VAC and 12-0-12, would have less deviation of voltage than the natural variation in line voltage. The heatsink has already burned off excess voltage for decades already. If it didn't burn off excess voltage then the voltage would go out of spec when the line input drops to 80% or whatever it is.
@@jagmarc my calculation says that 12 volt ac produces 15.6v DC after rectification. Isnt this a little low for the ta7179p to produce a consistent 15v +/= ? shouldnt there be more headroom ?(around 17vDC?)
@@COD-dr1ph a "12 volt" transformer puts out more than 12.0 VAC :) Hey, if does turn out lacking headroom you could swap the bridge for discrete schottky diodes with lower drop.
@@COD-dr1ph Converter transformers are available of course. 120 in and 240 out. About 50 usd.
Interesting, i would have started with the ac ,and worked my way in through the power supply.
So uhm, can I buy that 220 transformer from you? I’m in The Netherlands and have a 110 808.
I had a problem with the 15/-15 fuses on a 106 recently, they were blown, but when powered on, voltage still made it to the other side!! Somehow become semi conductors. With the power off they were open circuit, powered on they passed a low voltage : /
I suppose that you've also replaced all the other fuses and not just the broken one? 😉
man. i wish ALL my repair woes turned out to be due to a bad fuse...
🤘🤘🤘kannst du meine 909 wieder flott machen?
Wouldn't it be a step down transformer?
It is stepping our 117v up to 240v
@@sawsquaresinetube It's stepping down 240 down to 110
@@newking70 the owners existing line voltage is 110v, the unit required 220v line voltage, so the owner used a step-up transformer to change line voltage from 110v to 220v. Now replacing the units existing internal transformer to one that has an input AC voltage of 110v eliminates the need to use an external step-up transformer.
a step *_down_* transformer would be used for powering a 100-120v appliance in a 220-240v country, whereas in this case, a step *_up_* transformer was being used to power a 220-240v appliance in a 120v country.
he then simply replaced the 808's internal 220-240v-input transformer with a 120v-input transformer, effectively changing the 808 from a European one to an American one and eliminating the need to use an extra external (step up) transformer.
What blows my "fuse" is the fact that you replaced that one bad fuse with a fresh new shiney one and left the other 3 dull old ones in there... after complaining about the low quality junky fuses that were in it...
You could've removed the fuse with any basic Vanderweiss tool.
Fuse... chaser