Hello!
Just got my hands on a broken Ibanez DL-10. Unfortunately there does not seem to be schematic available for this one, so debugging is bit hard. Someone seems to have messed with it earlier, so if anyone has one around I could use some values.
No voltage is coming to the ICs. So far I have noticed that transistor TR3 has blown and the zener ZD1 is replaced with two other diodes. If somebody owns one, could really use the original value of the zener and the model of the transistor. Both are located at the bottom left corner of the PCB when looking from the component side.
Thanks a lot in advance!
Hello,
Hi there! It sounds like you've got quite the project on your hands with that Ibanez DL-10. It's great that you've already identified some of the issues, like the blown transistor TR3 and the replaced zener diode ZD1.
Unfortunately, it seems that schematics for the Ibanez DL-10 are not readily available online. However, based on similar models and general knowledge of delay pedals, here are some suggestions:
Transistor TR3: For the transistor, a common replacement might be a 2N3906 (PNP transistor) or 2N3904 (NPN transistor), but it's best to verify with the original part if possible.
Zener Diode ZD1: The zener diode is likely used for voltage regulation. A common value for zener diodes in audio equipment is around 5.1V or 9.1V, but again, verifying the original part would be ideal.
Thanks for the reply! Yeah, those would be the ideal actions, but unfortunately the transistor cant be identified since its pretty badly melted. Middle pin is attached to 9V and left pin to ground, so I guess it might be C1815 which is used in other places in the pedal as well (would match the pinout since the collector is the middle one).
As mentioned zener seems to have been replaced earlier because there is two diodes in series in that spot and the soldering looks different than the original ones on the board.
Lets see if someone happens to have one lying around and is willing to pop it open. :) Tried googling for one evening, but did not find any high resolution pics that could be used to identify the parts.
Did little bit of investigation with multimeter. If the pinout is same as C1815 it seems that the transistors collector is tied to +9V, emitter to +9V via that zener and base to the VCC of the ICs that require +5V (like the main echo chip, M50195p). Soo, I guess its supposed to work as voltage regulator to create that +5V line and based on that the zener probably should be 5,1V one. ;D
jebus, please, don't engage the ai bots.
Quote from: Jebus on February 19, 2025, 08:53:44 AMDid little bit of investigation with multimeter. If the pinout is same as C1815 it seems that the transistors collector is tied to +9V, emitter to +9V via that zener and base to the VCC of the ICs that require +5V (like the main echo chip, M50195p). Soo, I guess its supposed to work as voltage regulator to create that +5V line and based on that the zener probably should be 5,1V one. ;D
well that won't work. a Vbe multiplier would have the collector to external 9V, the base to the zener to set the voltage, and the emitter to the circuit wanting clean supply. if someone replaced the transistor with the wrong pinout, it might well meltdown.
that bit of circuit should be commmon to a great many Ibanez supplies.
Quote from: duck_arse on February 19, 2025, 09:38:02 AMQuote from: Jebus on February 19, 2025, 08:53:44 AMDid little bit of investigation with multimeter. If the pinout is same as C1815 it seems that the transistors collector is tied to +9V, emitter to +9V via that zener and base to the VCC of the ICs that require +5V (like the main echo chip, M50195p). Soo, I guess its supposed to work as voltage regulator to create that +5V line and based on that the zener probably should be 5,1V one. ;D
well that won't work. a Vbe multiplier would have the collector to external 9V, the base to the zener to set the voltage, and the emitter to the circuit wanting clean supply. if someone replaced the transistor with the wrong pinout, it might well meltdown.
Might be just my mistake, been way too many years since my electronics studies. Thank you, I will try it out like that. Hopefully nothing new melts.
On some DL-05 models, your "TR3" is a 3-pin regulator IC, and the Zener(s) are unrelated, go to the LED.
A 3-pin regulator IC normally won't go "pretty badly melted" because self-protection. (Unless it was fed AC: the self-protection may only work one way, the maker doesn't want to say.)
(https://i.postimg.cc/rDXzgd6K/backboard.jpg) (https://postimg.cc/rDXzgd6K)
(https://i.postimg.cc/sMYxLVyK/board.jpg) (https://postimg.cc/sMYxLVyK)
(https://i.postimg.cc/B8N6qMjK/DL10-guts1.jpg) (https://postimg.cc/B8N6qMjK)
(https://i.postimg.cc/Z9Jnt15m/DL10-guts2.jpg) (https://postimg.cc/Z9Jnt15m)
The DL-5 would be a good place to start,
https://schematicheaven.net/effects/ibanez_dl5_digitaldelay.pdf
(This schematic looks very much like a relabeled DOD schematic.
There's another one here,
https://zeninstruments.blogspot.com/
but that could just be a redraw of the of previous one.)
Even the PCB looks remarkably similar,
https://mirosol.kapsi.fi/2014/04/ibanez-dl5-digital-delay/
I put 5.1V zener and 2n5088 in there, now the 5V line is working and the ICs are getting voltage. The bypass is not working (led stuck in on state) and there's no signal passing through. I think the DL-5 schematic and audioprobe could be good next step to figure out where the signal cuts.
I just got a DL10 with at least the same issue, smoked TR3. It is indeed a C1815 originally. It's not in the signal path though, so I wouldn't be to fussy about a specific replacement as long as it's NPN. The Zener is marked 5.6.
Simply replacing TR3 didn't do much for me, the new one (harvested another from the poti-board) still gets hot very quick so I first need to find the cause for this. Looks like the circuit is doing the job of an 7805 here, providing VCC 5V for the digital chips.
Mine has some heavy "toast marks" under the IC1 socket as well, so I expect some more surprises with mine.
Follow up: I isolated the RAM-chip from vcc, without it power draw is 50mA and TR3 shows no sign of heating up. Connecting the RAM adds 100mA to the power draw, which is a good bit out of spec for this chip (KM4164B data sheet notes a max of 60 mA), so I suspect it is to blame here and ordered a replacement.
The toast marks under IC1 seem to be an old problem another fixer dealt with, my opamps sit in IC sockets which are not in place in the original units and don't show any problems now.
Quote from: dxbln on March 31, 2025, 09:24:26 AMMine has some heavy "toast marks" under the IC1 socket as well ....
photos of same?
and welcome to the forum.
Quote from: duck_arse on March 31, 2025, 09:43:01 AMphotos of same?
here you go:
(https://i.postimg.cc/Hjjzr03n/Unknown-1.jpg) (https://postimg.cc/Hjjzr03n)
(https://i.postimg.cc/mhqwCc6w/Unknown.jpg) (https://postimg.cc/mhqwCc6w)
(https://i.postimg.cc/sMC4HkzG/IMG-1015.jpg) (https://postimg.cc/sMC4HkzG)
(https://i.postimg.cc/0MjYJxYF/IMG-1017.jpg) (https://postimg.cc/0MjYJxYF)
As mentioned, the heat problem with IC1 already was the concern of somebody else by the looks of it, whose soldering skills I better not start lamenting :) In any case none of the opamps are acting strange now.
Since I bought it on my local version of Craigslist as defect for 20€, there is hardly any room for regret.
In it's current state, without the RAM, the 2 remaining chips feeding off 5V VCC are not emanating any smoke and the delay clock is clocking nicely with TR3 not sweating at all. Now I have to wait until that replacement RAM chips arrive until any more insight can be gained here.
it would be interesting to see what was left of the IC1 that left that mess. and the IC got so hot to burn, but there's no heat signs underneath.
Quote from: duck_arse on April 02, 2025, 09:39:49 AMbut there's no heat signs underneath
Oh there is, see 3rd pic in my post. I have absolutely no idea what would have to be done to a mere op-amp to melt and leave such very toasty mark on the pcb. Since it was replaced by someone before I got the pedal, I can offer neither clues or more evidence here.
The only thing I can deliver is a somewhat anticlimactic update to the state of my formerly broken DL-10 pedal: 'Xin Feng Tai Shen Electronics' delivered an economic replacement RAM chip, which inserted into the socket I installed before now does its memory thing without heating poor T3 to death and the thing is alive again. Apparently also such rather unsespecting digital parts can go rogue and mess things up. Before I always just saw them die without inflicting collateral damage. Life is an endless lesson.