Identifying transistor on PS1 controller - Page 1
Forum section: electronics / repair

author: Part Time Commie
author_rank: Contributor
timestamp: September 02, 2025, 09:00:48 pm
content: Hello,I bought a broken PS1 controller that have the big vibro-motor not working. After testing it I found that the motor is good, what is not fine is the voltage received. It gets 3.5V instead of 5-8V required to run. I identified what seems to be a NPN transistor (see attached image).The collector (C) has 5-8V and the base (B) 0.3V at rest (seems a little bit high).When I request the vibration it gets 3.5V at the base and outputs 3.5V from the emitter (E) which seems to be only the voltage from the base, nothing added from the collector.I am trying to find a replacement with the right specs, but I am nto experienced enough to tell what it would be. you can read DA0D on it and I tried to google that but couldn't find anything.While the transistor seems defective, I also think that the 3.5V for a base pin of a transistor is a bit high, given that you usually need only 0.6V to activate it, but I am not experienced enough to tell, that could just make sens to add 3.5V and 5-8V to run the big motor. Maybe the issue is that it's getting to much voltage at the base pin and the broke the transistor?Any insight is appreciated.Thanks.

author: Whales
author_rank: Super Contributor
timestamp: September 02, 2025, 10:19:15 pm
content: Could you please post a photo of the whole PCB? That would also help identify the model, then we might be able to find a schematic that can give hints.I can only find one model of official PS1 controller with a vibration motor and it was released in japan, the north american version apparently didn't. Maybe this is a PS2 dualshock in grey, or a third part controller? IDK.

author: Part Time Commie
author_rank: Contributor
timestamp: September 02, 2025, 10:25:38 pm
content: I could be a very early PS2 controller or very late PS1. It's very high quality so I doubt it's third party. The analog boxes moving parts are all metal.If you find one schematic, that ressemble this, I assume the transistor would be almost identical, no?

author: fzabkar
author_rank: Super Contributor
timestamp: September 03, 2025, 04:17:15 am
content: What are the voltages on pins 1,2,3 of U3 (NJM2904)?https://datasheet4u.com/pdf-down/N/J/M/NJM2904_NewJapanRadio.pdf"DA" appears to be an NPN BJT, 2SD1664.

author: Part Time Commie
author_rank: Contributor
timestamp: September 03, 2025, 11:16:11 am
content: If the order of the pins are as I think they are:1(B) 0.3V at rest and 3.5V when active2(C) 5-8V (5 in USB, 8 on the real console)3(E) 3.5V (this should be at least 5V)2SD1664 seems to match more than NJM2904.

author: wraper
author_rank: Unknown
timestamp: September 03, 2025, 11:28:07 am
content: It's an emitter follower circuit. It will never output voltage higher than on base and it should be about 0.6V lower than base voltage under load.

author: fzabkar
author_rank: Super Contributor
timestamp: September 03, 2025, 04:30:11 pm
content: Quote from: Part Time Commie on September 03, 2025, 11:16:11 amU3 is the IC that is driving the transistor. I was asking for the voltages at the IC, not the transistor.

author: Part Time Commie
author_rank: Contributor
timestamp: September 03, 2025, 06:59:06 pm
content: My bad, that's why I was confused.1: 3.5v2: 2.1v3: 3.15vAfter wraper's comment, I went en rechecked the voltage for the emitter pin and it is about 0.6V so it,s 3.0 instead of 3.5v.

author: fzabkar
author_rank: Super Contributor
timestamp: September 03, 2025, 07:15:17 pm
content: The output of the op amp should be hitting its positive supply rail. What is the Vcc voltage on pin #8?

author: Part Time Commie
author_rank: Contributor
timestamp: September 03, 2025, 07:21:54 pm
content: 5V, it's directly connected to the same 5V as the collector pin of the BJT.

author: fzabkar
author_rank: Super Contributor
timestamp: September 03, 2025, 07:31:12 pm
content: It does appear that the op amp is outputting its maximum voltage when the supply is 5V:Code:Maximum Output Voltage Swing VOPP RL=2kΩ 3.5VInput Common Mode Voltage Range VICM 0~3.5VTherefore it appears that the motor is designed for 3V drive.

author: Part Time Commie
author_rank: Contributor
timestamp: September 03, 2025, 08:33:34 pm
content: Seems strange because there is a smaller motor on the pad which has 5V going through it and when I put the big motor in an xbox controller where a very similar big motor would be (also running at 5V) it works. I tested another working big motor from a dualshock 2 in the broken dualshock 1 and it wouldn't work either.It running on 3V wouldn't make the existence of this higher voltage line a bit strange? Why is the NPN BJT getting 5V at its collector but outputting 3V at the emitter?

author: fzabkar
author_rank: Super Contributor
timestamp: September 03, 2025, 08:40:07 pm
content: Quote from: Part Time Commie on September 03, 2025, 08:33:34 pmBecause the op amp can only output 3.5V when its supply is 5V.

author: Part Time Commie
author_rank: Contributor
timestamp: September 03, 2025, 09:00:52 pm
content: Thanks I think I understand better now. It's using a "common collector" circuit or "emitter follower" wraper said. Those do not gain voltage, only current. I though all transistors would combine voltage.Essentially everything is fine and the motor is probably at fault? Which would be weird given that it works in another circuit.

author: wraper
author_rank: Unknown
timestamp: September 03, 2025, 09:39:10 pm
content: There appears to be liquid damage / corrosion on this board. I suggest to remove the board and look what's happening on the other side.

author: Part Time Commie
author_rank: Contributor
timestamp: September 03, 2025, 10:35:19 pm
content: I just tested the through holes and they are fine, there is nothing wrong on the other side of the board. I also tested the capacitors for shorts. I think this is just glue from the ribbon cable, it used to be glued down at the spot.

author: Part Time Commie
author_rank: Contributor
timestamp: September 07, 2025, 08:26:25 pm
content: I though about it some more and if the transistor is in a emitter follower circuit then the point iscurrent gain, right? so if the voltage coming from the U3 and the base to emitter pin correct, then maybe the current that should be added from the collector pin is not.I tested the current going from both pads of the motor with the motor removed and I got 0.26A on my deffective PS1 controller. I checked on an xbox controller with a similar motor (a controller that can actually drive the motor from the defective controller) and I got 0.36A (motor unplugged). It might be missing a whole 0.1A from the transistor.Does that seem plausible?

author: Whales
author_rank: Super Contributor
timestamp: September 07, 2025, 08:42:17 pm
content: 0.26A vs 0.36A for completely different models of motor is similar enough to be acceptable.Are you sure the vibration motor itself isn't bad?QuoteThat could mean there is too much friction in the motor, ie it has worn, lost lubricant or filled with debris. Any such motor can be made to work by applying more voltage.QuoteThat's normal for an emitter-follower (common collector) circuit. The emitter will be approx 2V below the collector at this current level.

author: Part Time Commie
author_rank: Contributor
timestamp: September 07, 2025, 09:02:54 pm
content: I can't be 100% sure that the motor itself isn't bad, but it seems in rather decent condition. It works on the Xbox Controller and if I put a PS2 motor in the PS1 controller, it still does not work. All vibrators from that era are so similar you wonder if they didn't all come from the same place. There's some rust outside but the motor can spin by itself by just putting the weight upside so it falls down. I can't feel any resistance if I try to move it manually.I might leave it at that and wait until I come across a more similar version to swap parts and make some more conclusive tests.So far my guess i that either the transistor is bad and not adding the current or the motor is bad.Now that I think about it, I should desolder the smaller motor and check the amps there.Update:OG Xbox:Small 0.35ABig 0.37APS1:Small 0.15ABig 0.25ASo the amps might be all fine and maybe the motor is bad in an imperceptible way. I'll leave it at that until I get another one to compare.Thanks everyone for your help.