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Lithium_Grim wrote:Then there is a high change you got a defective max1044. Try to replace it.

Starting to make sense...I was getting U1 and IC1 confused when looking at the diagram. U1 (LT1054CP) charge pump is overheating, so just ordered a couple from Mouser.

Am I correct that a LT1054CP can replace the MAX1044 in IC1 also?

No, an ICL7660S replaces a max1044, not a LT1054. Note that pin 1 and 8 are connected together in both 1044's. A 1054 can only replace it when you break the trace connecting pin 1 and 8!!!

The main difference between the 1054 and 7660S (note the s at the end!!!) is that the 1054 can deliver more current and is more pricy than the 7660S. But also the 7660S needs to have pin 1 and 8 connected together else it may tend to make your effect squeal like a pig. the 1054 must not have pin 1 and 8 connected. If a 1054/7660 heats up there can be more wrong! Check all caps surrounding the 1044s especially C6,C7,C10, C14,C15,C27 and check polarity. Note the @-9V the polarity of the caps are reversed! If you do not check this, you might replace a 1044 just to find out that you are blowing it up again.

Lithium_Grim wrote:No, an ICL7660S replaces a max1044, not a LT1054. Note that pin 1 and 8 are connected together in both 1044's. A 1054 can only replace it when you break the trace connecting pin 1 and 8!!!

The main difference between the 1054 and 7660S (note the s at the end!!!) is that the 1054 can deliver more current and is more pricy than the 7660S. But also the 7660S needs to have pin 1 and 8 connected together else it may tend to make your effect squeal like a pig. the 1054 must not have pin 1 and 8 connected. If a 1054/7660 heats up there can be more wrong! Check all caps surrounding the 1044s especially C6,C7,C10, C14,C15,C27 and check polarity. Note the @-9V the polarity of the caps are reversed! If you do not check this, you might replace a 1044 just to find out that you are blowing it up again.

UPDATE: Small success...I replaced the U1 with the same chip the LT1054CP and at least the boost started working again. (Boost quit working after chip overheated) I ordered a couple ICL7660S to replace IC1.

QUESTION: My unit came with a MAX1044 in IC1 and a LT1054CP in U1 (as does the gut shot reflects in the beginning of this thread). It appears there is a trace connecting pins 1 to 8 on both U1 & IC1. Is this a mistake on the manufacturers part as far as substituting the wrong chips?

*EDIT#2: In other words, there should NOT have been a LT1054CP in U1 from the factory, if the circuit board trace is connecting pin 1 & 8...correct?

I did some research. Looks like my info is very outdated. There is no problem connecting pin 1 and 8 anymore with a LT1054. Source: https://www.diystompboxes.com/smfforum/ ... c=112200.0

Lithium_Grim wrote:I did some research. Looks like my info is very outdated. There is no problem connecting pin 1 and 8 anymore with a LT1054. Source: https://www.diystompboxes.com/smfforum/ ... c=112200.0

Cool...good to know. I've read that a MAX1044 max voltage is 10v and that powering it with a single One-Spot supply producing 9.45v and 1700ma is asking for trouble...and that's exactly what the guy I sold it to was powering it with.

Yes, a 7660S is rated at max +13V and is a safer bet.

Lithium_Grim wrote:Yes, a 7660S is rated at max +13V and is a safer bet.

Well...i'm in the home stretch. Replaced the MAX1044 in IC1 with an LT1054CP and I have signal passing thru now! Bad news is that there's the squeal that everyone refers to.

I have some 7660S coming in a few days, so will switch it out.

EDIT: Turned the gain down, plugged my guitar in and she is rockin' again! No squeal at reasonable gain settings.

Enjoy! PS. No need to replace the 1054 with 7660S.

Pedal sounds great...however it has a crackle so there is probably a bad cap.

- While replacing IC1 7660S made the drive side work again, I still do NOT get a negative dc voltage off of pin 5. Decoupling cap connecting pins 2 & 4 bad maybe....?

Used the board from Lithium_Grim



Build report and demos coming soon....fits in nicely with the rest of the crew

It is a beauty! But I am biased

Lithium_Grim wrote:If (like me) you experience strange behavior when in boost only mode and turning the volume of your guitar down then consider putting a 10K between your guitar and the input of the Boost section. like this (Rx):

Bogner La Grange modified Boost.JPG

You could also consider to put Rx after C6 instead of before. Also you might consider a lower value then 10k (eg. 1k) if you think it is snooping off too much bass.

Personally I prefer this:

Bogner La Grange modified Boost pref.JPG

what does the zener diode do?

The Zener is there to protect the mosfet against possible static.

Lithium_Grim wrote:The Zener is there to protect the mosfet against possible static.

thank you very much

nycLPplayer wrote:Used the board from Lithium_Grim

[ Image ]

Build report and demos coming soon....fits in nicely with the rest of the crew

[ Image ]

Love the mouse/rat trap enclosure.

nycLPplayer wrote: ↑23 May 2018, 03:36 Used the board from Lithium_Grim



Build report and demos coming soon....fits in nicely with the rest of the crew

Looks beautiful!
Can you do me a favor and post a picture of the insides? I'm trying to fit the same PCB into an enclosure and can't quite figure out how to place things.

Could someone repost Saruman's schematic?

Thanks!!

Look at the end of the first post. Somehow the schematic was attached as a link only.

Hi there
Sorry for the necrobump but I've just acquired a La Grange and I've noticed some faults with it. I tried looking for a schematic and this site came up.

The gain control doesn't do anything past 12 o'clock
The Variac has no effect on the sound
The Structure switch has no effect on sound

Having opened it up, the first thing I noticed were the two voltage converters (IC1 and U1) have pins 1 and 8 folded away, these are both 7660S CPAZ's. I tried refitting these with pins 1 & 8 connected which produced a high pitch noise.

I tested the gain pot in situ and it appears to be working fine.

If anyone could point me in the right direction I'd be really grateful!
Cheers
Ronnie

Can you attach a picture of the 7660D so we can see how these pins are folded? I have never seen a "D" before and can't find a data sheet on it.

Depending on the IC model, pins 1 and 8 are either connected or not. Pin 8 is the V+ input and Pin 5 is the Vout. If pin 8 does not receive a connection, that IC is not doing anything.