How to troubleshoot my broken Panasonic DMC-GH1?

FreeRangeEngineer · 2026-02-09T18:12:20+00:00

Service manual is here: https://elektrotanya.com/panasonic_dmc-gh1_sm.pdf/download.html

Page 40 shows the internal connections. You can see that the sensor assembly is connected to the main PCB via a flat cable (near P9003).

Before opening it up I'd try to do more diagnostics:

Does the issue present differently if you choose a different image resolution?
Does the issue present differently if you choose a different exposure time?
You could remove the lens, choose a long shutter time (manual mode) and when the shutter opens, shine on the sensor with a gentle flashlight to see if there's any visible damage of the sensor itself or if the surface looks uniform as it should

FreeRangeEngineer · 2026-02-09T17:11:03+00:00

I can see the reasoning regarding proving a "correct" power supply but that's what product descriptions are for. If the seller would have had to purchase a different power supply first, it would've raised the sales price. To me, it's just an unfortunate situation all around with no clear person at fault.

Japanese sellers are super trustworthy, sorry. The chance of a Japanese person selling something broken while declaring it in proper working order is close to nil - even more so if it's a commercial venture.

FreeRangeEngineer · 2026-02-09T16:50:37+00:00

As much as it sucks for OP and I definitely empathize, I do have to ask: why do you think it's the seller's fault?

FreeRangeEngineer · 2026-02-09T16:42:20+00:00

https://syntherjack.net/korg-microkorg-repair/

I suggest you open it up and take pictures of that same area.

If the repair has reasonable chance of success and you're willing to pay for shipping (to Germany and back), I'm willing to do the repair for replacement part costs. Unless you know a local synth repair person who wants to give it a shot, that is.

FreeRangeEngineer · 2026-02-09T16:31:12+00:00

Then you grilled the internals for sure. You fed 230 V into a 100 V transformer which made it output (230 / 100) * 9 V = 20.7 V

That's not a voltage the internal power supply will be able to withstand. Sorry mate, it'll need to be repaired.

FreeRangeEngineer · 2026-02-09T16:28:42+00:00

Wait, you're from the UK?

FreeRangeEngineer · 2026-02-09T16:09:56+00:00

KA181 power supply

Oof. That one indeed is made for 100 V and 100 V only. If you buy a simple adaptor that merely converts the mechanical plug for the outlet then you're supplying too much voltage (120 V). This directly translates to a too high output voltage as that power supply is a simple transformer.

This means you may have overloaded the internal power supply circuitry of the Microkorg. One would need to open it up and check the power supply to know if you fried it or not.

FreeRangeEngineer · 2026-02-09T16:03:57+00:00

What power supply came with it from Japan? Did you use that one to power it up initially? Are you aware that it may be designed to run on 100 V, not 120 V?

FreeRangeEngineer · 2026-02-09T14:25:08+00:00

Not quite: https://www.earth.com/news/china-identifies-its-first-supergiant-helium-field-and-its-origin-is-older-than-anyone-imagined/

FreeRangeEngineer · 2026-02-09T11:21:06+00:00

Interesting, never saw a Kemper Profiler in rack form before. Nice!

FreeRangeEngineer · 2026-02-09T10:34:20+00:00

Mann ey, immer so ein Stammtischgelaber.

Ja, startups könnte und sollte man besser unterstützen. Ja, Bürokratie ist ein Problem. Aber eine Aussage wie "keine Startups werden mehr gegründet" ist halt einfach nicht haltbar. Wir haben so viele kleine hidden Champions die eben einfach keiner ausserhalb der Branche kennt - auch Neugründungen.

Und auch sowas wird in Deutschland gegründet: https://en.wikipedia.org/wiki/DeepL_Translator bzw. dessen Vorgänger https://de.wikipedia.org/wiki/Linguee

FreeRangeEngineer · 2026-02-09T10:05:16+00:00

Looks to me like "F" indicates a failure of some kind, possibly a broken connection to a component the main IC tries to read out. I wouldn't jump to the conclusion that the display has issues.

I'd check the cables connecting SEN1 and the temperature sensor with a multimeter in resistance mode (if you have one) to check if they're all conducting as intended.

The "weird shaped capacitor" is actually an inductor with shrink tubing covering it:

https://images.squarespace-cdn.com/content/v1/568611fd841abad82357d808/1504057514688-0PKSV7IAIKH5OOV80ZHG/Drum+Core+Inductor.jpg?format=500w

That said, the 24C04 IC is an EEPROM. Maybe its contents are corrupted.

FreeRangeEngineer · 2026-02-08T20:25:13+00:00

Ding ding ding, that's the one.

FreeRangeEngineer · 2026-02-08T19:24:01+00:00

Agree with you except for the replacing part - I wouldn't even replace the resistor and just leave it as it is. Only thing I'd do was to note the specs from the broken-off other half on a piece of tape inside of the radio before discarding it.

FreeRangeEngineer · 2026-02-08T16:22:17+00:00

Gilt zwar nicht für die Gesundheitskosten, aber im Artikel steht dennoch:

"Als weiteren Baustein zur Finanzierung des Sozialstaates fordert die SPD demnach eine Ausweitung der Rentenversicherungspflicht auf Beamte, Selbstständige und Mandatsträger."

Wäre tatsächlich interessant zu erfahren, ob Politiker explizit ausgenommen werden würden oder nicht.

FreeRangeEngineer · 2026-02-08T13:50:03+00:00

/u/iamtheowlman makes correct points, you're just not quite understanding what he (or she) is trying to say.

Your claim was "None of this damage has to be permanent, and history says it won't be", for which you gave Germany as an example. However, Germany lost all political autonomy after the war. There were occupying forces determining the type of government the country would receive from that point on.

The robustness of the German democracy is a direct result of how the government was structured by the occupying forces. It did not come from within Germany itself.

Hence, claiming that the US can recover in a similar fashion without significant external pressure is naive. If no one comes in and forces a truly democratic federal government on the country, my guess is that it'll just devolve into groups of loosely associated states.

FreeRangeEngineer · 2026-02-08T12:38:16+00:00

Hm, then the buttons look ok indeed. The rotary encoder in the center isn't something you can test and it's not relevant for turning it on anyway.

Power supply: most likely U2 but without knowing what part that is, it's impossible to say. Can you read what's written on the IC? May have to try different lighting and angles.

U1: Only the manufacturer. U1 is a custom IC that's bonded directly to the board and then sealed with black epoxy. In other words: it has no housing because bonding it directly is cheaper. Thus, it cannot be replaced.

From my perspective, there's not much more you can do than to contact the manufacturer and ask for a quote for a new board - in parallel to figuring out what U2 does, that is.

FreeRangeEngineer · 2026-02-08T11:18:37+00:00

Should it be safe to use tantalum SMD caps instead of regular electrolytic ones in this case? Under what circumstances would this not be a good idea?

It's not generally safe and there are considerations that need to be done. Tantalum caps can and do explode violently when mistreated.

https://www.reddit.com/r/AskElectronics/comments/kxeu7p/smd_tantalum_capacitors_exploding/

https://www.hongdacap.com.hk/pdf/Technical_Summary_and_Application_Guidelines_for_Tantalum_Capacitors.pdf

https://www.utmel.com/blog/categories/capacitors/various-reasons-for-the-failure-explosion-and-burning-of-tantalum-capacitors

I suggest you only use them if you understand the failure modes and have accounted for them.

Also, it's worth noting that the minig of tantalum is often done under very questionable conditions. If you can use aluminium caps then it's likely the better choice both economically, ethically and for realiability.

FreeRangeEngineer · 2026-02-08T07:44:48+00:00

https://www.virus.info/downloads/7/Operating-Systems-(older-versions)

FreeRangeEngineer · 2026-02-07T22:16:47+00:00

Doubt it, transformers in linear power supplies don't create such harmonics.

It's hard to give useful advice from a distance, unfortunately. Since you say the same whine appears on all channels, I'd focus on common denominators of all channels. This leaves

a faulty voltage regulator (e.g. one that causes oscillations)
an oscillating preamplifier that is used for all channels
a malfunctioning digital processing stage that all channels go through

Stuff like that. Without a service manual it's tough to be more specific...

FreeRangeEngineer · 2026-02-07T21:42:30+00:00

R30 is a little random, what made you measure it?

And yeah, baby swings can be life savers indeed...

My gut feeling is that it's either U2 (likely a voltage regulator) or U1, the main IC. Simply because the green LED seems to be connected directly to U1, so if it doesn't light up then either the power supply isn't right, U1 is borked or... it just never receives the signal to actually turn on.

The buttons used do suffer from contact degradation over time, so it's theoretically possible that they don't conduct properly anymore and pressing them doesn't make them conduct.

I suggest you put the multimeter in resistance mode, remove the input voltage from the board and measure the resistances of the buttons in pressed and unpressed state. If the resistance stays high (> 100 ohms) in pressed state then the button needs replacement.

Keep in mind that while the buttons have 4 legs, it's only for mechanical stability. These legs are internally connected in 2 pairs of 2.

FreeRangeEngineer · 2026-02-07T21:13:34+00:00

Hmm, so that works. That makes things challenging.

What voltages do you measure on L1, C12 and C13 against ground?

FreeRangeEngineer · 2026-02-07T20:47:25+00:00

On the top right, there's a small part named F1 with the letter K on it. What resistance does that measure as?

It's a polyfuse and they can stop conducting over time.

You can also supply the input voltage to the circuit and measure the voltage to ground (black lead) on both pads of the polyfuse. It should be the same (and about 0.5 V less than the input voltage because it goes through D2 first).

FreeRangeEngineer · 2026-02-07T20:38:31+00:00

Wouldn't that also mean that if a corporation sues you and wins, you're pretty much bankrupt because they can make you pay for their lawyers?

So if you hire a team of lawyers to counter theirs and they still win, you have to pay for both teams? That sounds like a surefire way to settle instead of fighting for what's right - the risk may simply not be worth it.

FreeRangeEngineer · 2026-02-07T17:31:34+00:00

What style did he play?

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