AGA MK3 - Received, but decoupling cap C1 missing....

Fatcat · Sep 7th 2020

Hello,

I received my AGA MK3 this morning, Thanks. Only a 14 day journey from Germany to New Zealand.

I was doing a QA check, before I go about installing it and noticed that the decoupling capacitor C1 was missing from it's pads. See photos below. There had been one in place and you can see a couple of scuff marks on the RHS of the pads. So I suspect it has taken a knock at sometime.

How critical is this decoupling capacitor for reliable operation of that memory chip. I will be running it in a 1D1 board with Blizzard 1260/50 (64MB) & Scsi IV Kit (with powered CD Rom Drive), a 4GB/8GB CF drive and a Gotek drive. That's about all the extra noise i will be introducing :o) and my original Commodore 4.3A power brick.

Can I leave this cap out out or shall I fit a replacement one? I don't have any issues with fitting a replacement cap myself, if you tell me what the value is.

Now off to read the other posts for post-installation tips and tricks..

Regards,

Andrew

Jens · Sep 7th 2020

Quote from Fatcat

I was doing a QA check, before I go about installing it and noticed that the decoupling capacitor C1 was missing from it's pads.

Can you please share the Warranty ID of this unit? I'd like to take a look at our QC photos.

The capacitor is a 100nF/50V/0201 cap between 3.3V and GND - one of many, and the unit should work with and without with no recognizable difference. I'm just following the good practise to put a cap "near" every power pin, but given that the memory is clocked at under 140MHz and the board is a multilayer board with lots of capacitance between the power and GND layers anyway, I'd rate this mostly a cosmetic problem. If you have the skill and equipment to replace it, it will of course add to "the good feeling" Just share an updated picture of the area and the warranty ID, so we can add this to the database here. Your product warranty should not be affected if the part came off in transportation.

Note that we've changed the packing instructions already for Indivision AGA MK3, because we've had another case of a ripped-off part in the German part of this support forum. In that case, an inductor came off, so the H*MI encoder was without core voltage. The new packing includes a slightly larger antistatic bag and instructions to leave the adapter PCBs out of the bag.

Fatcat · Sep 8th 2020

See below for warranty label.

I will have to order some in as i only have 0805, 0603 and 0402 in that value/rating on hand. I will have to get 35V ones, as all my component suppliers only offer voltage rating upto 35v for that value in the 0201 size.

The caps most likely wont arrive until sometime next week, So this weekend I will install the indivision in without C1 in place and see if I get to experience 'the REAL good feeling' I am looking for without C1. If no issues, I will not worry about fitting C1. If any issues I will fit it when they arrive, to remove that from the equation. Not that I am expecting any issues.

I did see that posting in the german forum, that was the main reason why i checked my one.

I agree with your comments re the packaging. Removing the adaptors is a very good idea, the bag size is not a issue if adaptors are unplugged/removed.

Jens · Sep 8th 2020

Quote from Fatcat

I will have to get 35V ones, as all my component suppliers only offer voltage rating upto 35v for that value in the 0201 size.

Sorry about that - I didn't give you the correct rating here. What's assembled is 16V types, not 50V - the 50V rating is my standard rating for 0402 and 0603, but the 50V types in 0201 are prohibitively expensive. This product uses muRata 100nf/16V/0201/X7R.

Since these caps are on the 3.3V rail, you could even go down to 10V rating without too much derating.

Quote from Fatcat

I agree with your comments re the packaging. Removing the adaptors is a very good idea, the bag size is not a issue if adaptors are unplugged/removed.

Increasing the bag size has a different background: The closed box shall not rattle when you shake it

Fatcat · Sep 14th 2020

I have ordered some 0.1uF/16V/X7R/0201 capacitors, but they will not be here for another week or so via a USA supplier, as my local NZ/AU Suppiers want a min order of 1000/15000 pieces. So I will fit C1 when they arrive, if required.

I installed the AGA MK3 over the weekend into my 1D1 based 1200. The 1200, I had recapped it and it's been running a Blizzard 1260/50 and SCSI Kit with a Commodore 4.3A power brick for a few months now before fitting the AGA MK3 board. I do have another 4 x 1200's (1D1,1D4,2B and a unknown still sealed) waiting to be restored and capped as time allows. Can't have to many backup machines.

The installation was very straight forward.

RTFM....

Prepare and test the IndivisionAGAmk3.adf image on my Gotek drive.

Strip down the 1200 and used Isopropyl Alcohol to wipe down the legs on Lisa and CIA chips, then used a fibreglass pen to lightly brush the legs to remove 25+ years of contaminates/oxides and finally washed down with a bit more Isopropyl and a squirt of Canned Air. Both the sockets press fitted over the chips with a nice positive click.

When I recapped this 1200 I removed the RF Modulator, so I routed the VGA/HDMI adaptor board through that slot, as the usual (RHS) location I have the Blizzard SCSI 'D'connector located. I am not sure what the final solution is going to be with the VGA/HDMI adaptor yet, as the case is very open to case repair/modding/painting due to prior case damage before acquiring this 1200.

I connected up a Samsung VGA display, fired up the machine was was greeted with OSD then WB3.1.4. Firmware was already on V1.5 (ex IComp). Installed the IndivisionAGAmk3 tool onto the CF drive. Then I created a Rescue disk on my Gotek and had a bit of a play with the IndivisionAGA tool, attempting to learn the various functions/settings of the tool for a few hours on Saturday. Fortunately the Rescue disk is very handy.

Ran it for about 10 hours on Sunday. I still need to test operation with a HDMI display and learn how to tweak the settings. Found a few little issues (like a big mouse pointer (Prefs/Pointer tool), Dopus tool was 1.5 screens wide (adjusted Prefs/Overscan tool)), Protracker - no sound (Octomed - Ok), Jesus on E's demo glitched (sure this was mentioned in a another forum post). But this is more of a tweaking/settings thing and reading the IComp forums will iron out these things.

I was going to do more testing and make some notes, but unfortunately i had a small issue. I loaded 'Lost Vikings' and was blown away by how the colours 'Popped' and couldn't stop playing it. I very much like the Hotkey 'Live Configuration Menu' option especially for quick screen centering when playing games / watching demo's.

So that's where my testing ended for the the weekend.

Over the evenings this week I will have a better read of the IndivisionAGAMk3 manual and the the IComp forums to try and tweak it more and try out a HDMI display. (While my 2 x B2000's look at me in disgust every time i walk in the workshop, while bitching about being neglected and suffering varta damage, as I switch on my 1200.)

As to whether I fit the missing C1 - is a moot point now, with no observed hardware issues.