ASTRO-PHYSICSGTOCP4 UPGRADE AND INSTALLATION GUIDEIn order to determine which control box you currently have (GTOCP1, GTOCP2 or GTOCP3),
look for the model number printed vertically on the left side of the control panel.
(Note: Control boxes are often referred to simply as “CP2 or CP3, etc.” in the following text.)

IMPORTANT: Be sure to update your AP V2 ASCOM driver, APCC and APAE Utility software!
Also note that you’ll need to run a new PEM curve.

GTOCP4 Upgrade for Mach1GTO, 1100GTO, 1600GTO and 3600GTO Mounts
The process of upgrading from a CP3 to a CP4 control box on the Mach1GTO, 1100GTO, 1600GTO and 3600GTO
mounts is very straight forward. Remove the CP3 and replace with the CP4. Attach all the cables and you are done. It isthat easy...though there are a few caveats!
1600GTO:If you have an earlier 1600 mount, it may be necessary to remove the lanyard post (on the west side of the mount), as theCP4 is slightly wider. Simply unscrew the lanyard post and mount the CP4 in place of the CP3.
1100GTO-AE/L:
If you wish to use your current double Control Box Adapter, you can do so by mounting it off-center and then securing
the CP4 to the side. Alternatively, you can switch to the single Control Box Adapter (M11010KIT) as an aesthetic
consideration.
Absolute or Precision Encoders:If your 1100 or 1600 mount has the Absolute Encoders or your 3600 mount has the Precision Encoders (and/or Limit
Switches), then the respective GTOAE or GTOELS box will not be used, as the functionality of these boxes has been
incorporated into the CP4. Remove these boxes and the cables that connect them to the CP3 box. The 1100 and 1600
Encoder cable from the mount will plug directly into the CP4. The 3600 Encoder cable (and Limit Switches cable) will need
to be replaced with longer versions that will then plug directly into the CP4 box.

Parts required:●●

The GTOCP4 and Power Cable Set (CABPP4SET).

●●The 1100GTO-AE or 1100GTO-AEL also may use the Single Control Box Adapter (M11010KIT) in addition to theabove.

●●

The 3600GTOPE also requires a new Encoder Cable (CAB36PEF) in addition to the GTOCP4 and Power Cable
Set above.

●●3600GTO mounts with Limit Switches will also require a new Limit Switch Cable (CAB36LS4).

GTOCP4 Upgrade for 900GTO and 1200GTO Mounts
The process of upgrading from a CP1, CP2 or CP3 to a CP4 control box on the900GTO and 1200GTO mounts is a bit more complicated. There are two options
open to you for mounting the CP4 control box to these mounts. Because the CP4 isabout an inch wider, it cannot mount between the polar forks in the same orientation
as the older boxes.
Important Exception: If the 1200GTO mount is used at a latitude of approximately
37°-37.5° or higher, then the CP4 can be directly attached in the same fashion as wasthe CP2 and CP3 (no CBA912KIT needed). It will clear the polar forks.
First Note: If you feel that the angle of the control box will not allow adequate dew
runoff, we suggest that you purchase the Pier/Tripod Control Box Adapter (CBAPT)and attach the control box to the pier (described on the following page).

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Adapter (CBA912KIT)
to Rotate the CP4 90°

Second Note: Removal of the CP1 control box requires a specific procedure. Please see the illustrated instructions onthe following page. Once the CP1 is removed, then the upgrade path is similar to that of the CP2 and CP3 mounts.

Mounting to R.A. axis:
Note: When using the 90° Dovetail Adapter (CBA912KIT) the cable clearance under the dovetail saddle will be lessened,
requiring the cables to make a tighter bend. The creative use of aplastic zip tie to manage cables is recommended.
If you wish to mount the CP4 between the forks and use theoriginal Y-cable supplied with the mount, then you will need touse the 90° Dovetail Adapter (CBA912KIT) so that the box canbe rotated to fit. The 90° Dovetail Adapter attaches to the back of
the CP4 and allows it to be fastened to the mount. CP2 and CP3mounts already have the necessary dovetail bracket attached onthe R.A. axis for attaching the CP4 with CBA912KIT. See photoof the CBA912KIT on the CP4 at the bottom of previous page.
The original GTOCP1 box was of a different design that was fixed
directly to the R.A. axis. It did not have the convenient dovetailsystem for easy removal and replacement. Once the CP1 isremoved, upgrading from the CP1 mount requires adding a Servo900GTO
1200GTOBox Bracket to the R.A. housing in order to hold the control box
with its attached CBA912KIT adapter (see part numbers listed below). See the CP1 control box removal procedure on thefollowing page.
The upgrade path to R.A. axis mounting for the CP1 to CP4 also requires replacing the separate cables that were provided
with the CP1 system. A Y-cable, such as came with the CP2 and CP3 mounts, will be needed to complete your upgrade.

Parts required:●●The 900GTO and 1200GTO mounts upgrading from a CP2 or CP3 require the GTOCP4, Power Cable Set(CABPP4SET) and 90° Dovetail Adapter (CBA912KIT)*.
*See exception above regarding 1200GTO.

●●The 900GTO upgrading from a CP1 also requires the Servo Box Bracket (9CBKIT) and Y-cable (S900GYCR).

●●

The 1200GTO upgrading from a CP1 also requires the Servo Box Bracket (12CBKIT) and Y-cable (S1200GYCR).

Mounting to Pier Bracket:
Alternatively, by using the Control Box Adapter (CBAPT), originallydesigned for the Mach1GTO, the CP4 can be mounted to thesouth side of the mount’s pier. This is a very convenient wayto avoid accidental cable entanglements and to simplify cablemanagement. A longer Y-cable will be required for this option.
CP2 and CP3 mount owners should remove the Servo Box
Adapter from the R.A. axis (placing the button head screws backin the threaded holes to seal out dust and insects). CP1 mountowners will need to remove their control box. See the CP1 control
box removal procedure on the following page.
The screw to the lower hole should include the cable clip forsafely directing the cable path.
When mounting the CP4 in this lower position you will need touse a longer Y-cable. This applies to all CP1, CP2 and CP3owners.

900GTOParts required:●●1200GTO

The 900GTO requires the GTOCP4, Power Cable Set (CABPP4SET), Pier/Tripod Control Box Adapter (CBAPT)and longer Y-cable (SGYCR2345).

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●●The 1200GTO requires the GTOCP4, Power Cable Set (CABPP4SET), Pier/Tripod Control Box Adapter (CBAPT)and longer Y-cable (SGYCR2950).

Servo Box Adapter Install / Removal Procedure:

Removing Servo BoxAdapter

Installed Cable Clip

CP4 Attached to CBAPTGTOCP1 Control Box Removal Procedure:
Procedure
1. Remove all screws
shown in the illustration

Remove Screws (4)2. Lift off the box’s top

Remove Front
Corner Screws (4)Remove Screws(2 each side)

Remove Screws
in top row (3)3. Gently lift out the front
panel and internal electronics with the connected side sockets
4. Remove the two screws
that hold the CP1 housing to the R.A. axis (notshown)

GTOCP4 Upgrade for 400GTO and 600EGTO Mounts
Both 400GTO and 600EGTO mounts were shipped with two different motor/gear ratios during their production years.
These different ratios require that a different “personality” be programmed into the CP4 before it leaves our facilities. Theeasiest way to know which ratio your mount has is to open the top white panel of your CP1, CP2 or CP3 control box andsee what letter(s) are on the square chip inside. It will have either a “K” or “non-K” chip inside (example: “KD” or “D”). We
will need this information before we can send your CP4.
Upgrading the 400 and 600 mounts with the CP4 will require using the Pier/Tripod Control Box
Adapter (CBAPT) to attach to piers and tripods. There is no Pouch for the CP4 and its larger
size will not fit into your current Pouch. When attaching the bracket to tripods you will likely
also need to use the Control Box Extension Adapter (Q6280KIT) in order to have clearance.
It will not be necessary to replace the Servo Cable.

Parts required:●●

The 400GTO and 600EGTO mounts require the GTOCP4, Power Cable Set(CABPP4SET) and Pier/Tripod Control Box Adapter (CBAPT) (if you do not alreadyhave one).

●●

If using a tripod, both mounts may require the Control Box Extension Adapter(Q6280KIT).

3600EGTO

Information to Know When Selling or Purchasing aUsed CP2 or CP3 Control Box via the Second-Hand Market
There will be a number of used CP2 and CP3 control boxes becoming available through second-hand markets, such as
Astromart, once the CP4 is released. The buyer will need to be aware of a couple things to ensure that it will work with hisor her mount.
There are no concerns if the seller’s control box is from a Mach1, 900, 1100, 1200, or 1600 mount and being used on thebuyer’s 900 or 1200 mount as the mounts’ “personalities” are the same.
However, if the control box is either coming from a 400, 600 or 3600 mount or going to those mounts, then it will benecessary to change the “personality” setting of the control box. Please call Astro-Physics to learn more.
It is recommended that a CP2 or CP3 box have the latest chip installed in order to maximize its performance and safety.
Please call Astro-Physics to learn which chip is appropriate for your box, or check the technical support section of ourwebsite.
Although a CP3 will perform well with a “Q” and above chip, a “V”, “V1” or “V2” chip is recommended to maximize
performance, as well as being required to use the APCC software. There is no difference between these chips, exceptthat the “V2” is recommended for an 1100 or 1600 mount with absolute encoders. All of the “V” chips work the same for allother mounts.
Note: A CP1 or CP2 box cannot utilize the APCC software.
Finally, it is very important that PEM is turned off in the Keypad and disabled in the AP V2 ASCOM driver and APCC until a
new curve is run. If this is not done, then you will experience large and incorrect surges in the PE of the mount, as you will
be entering false PE curves that are from the previous owner’s mount into yours. Once you run a new curve, you can turnthe PE back on.

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